Ney York City College of Technology (BK)



WARSAW AGRICULTURAL UNIVERSITY

(SGGW)

SHEK GIBRILL SESAY

EFFECT OF LOW SOIL MOISTURE ON SOME PHYSIOLOGICAL PARAMETERS IN Amaranthus cruentus and Chenopodium quinoa

This study was carried out in the

Department of Plant Physiology,

under the supervision of dr. hab.

Tadeusz Loboda.

This work is in part fulfilment for

the award of the doctorate degree

in the Dept. of Plant Physiology.

WARSAW 1997

TABLE OF CONTENTS

Dedication (I)

Acknowledgement (II)

Chapter Page numbers

Introduction 1

I. Literature review 3

II. Methodology 28

III. Results 38

IV. Discussion 66

Bibliography 75

Appendix 144

(I)

This work is dedicated to my late father Alhaji Sheku Sesay who died in 1993, while I was still researching.

(II)

ACKNOWLEDGEMENT

I wish to thank my supervisor dr. hab.Tadeusz Loboda, for the constructive criticism, wise counseling and tremendous effort he generally expended in realizing this work..

I further wish to sincerely thank the entire staff of the Plant Physiology Department, of the Faculty of Agriculture, with high consideration due the head Prof. dr. hab. Emil Nalborczyk, for conducting the department in such a way as to enable this research, dr. Stefan Pietkiewicz, mgr Marzanna Gontarczyk, dr. Danuta Choluj and mgr Barbara Wawrzonowska.

I am also forever grateful to my friend mgr Bogna Cyprys and her family, she had been a constant source of consolation. I also wish to thank mgr James Ofwona for his help in typing the completed work.

I am also appreciative of my daughters’ efforts, Tity Gibrill-Sesay for waiting patiently during the research and Kadi Gibrill-Sesay, in helping me irrigate the plants.I also appreciative the efforts of my mother and other relatives who were devoid of my company and support during the research years.

many thanks to my Sierra Leonean colleagues for mutual support when one was in need of one.

INTRODUCTION

The ancient crops of Amaranthus cruentus (amaranth) and Chenopodium quinoa (quinoa) have in the recent past captivated the interest of researchers and the general public at large. As a result of this they have been referred to as promising “rediscovered” crops. The cultivation of these crops has far reaching historical background. Tapia (1982) reported that the cultivation of quinoa in the Andean highlands can be traced to 3000 BC. The high protein content of quinoa effectively recommended it as a meaningful alternative to the Andeans who lacked protein source such as meat and dairy products. Digging-up history holds that amaranth had been under cultivation in places around present-day Colorado, Mexico and some regions of Tamaulipus already since 4000 BC.

Survival of these crops to this day, after strong impact exerted by Christianity to halt their propagation is associated with several factors. In the case of amaranth its ornamental value was first recognized by the very religious groups that earlier decleared its propagation punishable. Later both crops were able to survive as a result of increasing interest in the cultivation of the pseudocereals. The increased interest was the result of a whole host of advantages which range from nutritional to industrial ones.

Currently elevated levels of essential amino acids have been discovered in these pseudocereals. Lysine is usually found in comparatively higher levels than in conventional cereal crops like maize, rice and wheat. An admixture of the two types of crops in the human diet, will lead to a balance of essential amino acids.

From the point of view of pharmacy it is noteworthy that both the inhibitors of LDL-cholesterol synthesis and a set of squalene have also been discovered in amaranth. Considering plant oils, squalene content of amaranth oil is high. About 1/400 of the seed weight or 5-8% of the seed oil (Lyon and Becker 1987).

Most plants from tropical to temperate zones do undergo some kind of moisture stress at some stage of their development. Low moisture strain in plants is an effect caused by the environmental stress of a decrease in the water level necessary for the plant to carry out its normal metabolism. Plant response can take various forms and the results are equally diverse including tolerance, susceptibility and prevention (Levitt 1972, 1980).

It is always the endeavour of research to reasonably quantify the responses, with a view of recommending appropriate agronomic practices and otherwise, necessary in enabling the plant to cope with the stress. The possible responses are from the sub-cellular level including change in the conformity of membrane-bound electron carriers or enzymes, implicated in various metabolic processes, to the whole plant level. Growth analysis, gaseous exchange measurement, radioactive tracers and nutrient composition analysis have insofar been used to follow the development of the pseudocereals since germination until final completion of the life cycle.

This study aims at comparing A. cruentus with C. quinoa in vegetative and generative crops in both the stressed and the unstressed combinations cultivated under Polish environmental conditions.

LITERATURE REVIEW

1.1 GEOGRAPHIC DISTRIBUTION OF THE CROPS

Amaranth can grow satisfactorily from sea level to above 3000 m, but only A. caudatus is known to thrive at altitudes of 3000 m in the Andean region and the Himalayas. Amaranth has been grown in geographic latitudes around 30O N and even in higher latitudes. As it is not frost tolerant, its production is limited to summer months in northern latitudes. However the requirement for a killing frost to facilitate harvest may provide production advantages for northern latitudes (Johnson et al. 1990). The crop grows best when the daily mean maximum temperature is at least 21O C. Various accessions have shown optimal germination at temperatures varying between 16O C and 35O C. The rate of emergence is increased at the upper end of the range. The growth of the plant ceases at 8O C and the plants are injured below 4O C. However A. caudatus being native to the Andes and high Himalayas is more resistant to chilling than A. hypochondriacus and A. cruentus. Weil et al. (1987) suggested that field emergence may be satisfactory with soil temperature between 18.5 and 24O C.

Carmen (1984) stated that quinoa is currently grown for its grain in the following South American countries: Argentina (North), Chile (Central and North), Bolivia, Peru, Ecuador and Colombia. According to Risi and Galwey (1984) quinoa is cultivated from sea level in South-Central Chile (40oS) to Southern Colombia (2oN) and from sea level to an altitude of about 3800 m. Indeed it is on the basis of this statement that a germplasm collection containing 294 accessions from this range of environment was screened for photoperiodic neutrality. Probably some genotypes that are from sea level ecotypes of South-Central Chile may well exhibit the characteristic of daylength neutrality.

Quinoa is cultivated at high altitudes in the Andes. Gandarillas (1968) described 17 races based upon morphological characters, while Galwey (1989) and Tapia 1979 proposed four main types based upon geographic location: the "valley" type, typical from 2000 to 4000 m in elevation; the "Altiplano" type, typical of highland areas above 4000 m in elevation; the "Salar" type of 4000 m but adapted to the high pH soils typical of the Atacama region; the "Sea level" types found in the inner valleys of Bolivia. They also reported that Wilson’s electrophoretic work has shown the "Sea level" type to be distinctly different from the other highland quinoas.

1.2 USES

Notwithstanding the fact that amaranth is a pseudocereal it can be used in many ways similar to our better-known cereals. The following major characteristics have been found recommending in the uses of amaranth. First it has been found to have a protein level ranging between 13 and 19%. Equally important is the relatively high lipid content compared with other cereals (Bressani, 1990). The micro-crystalline starch granules have been found to be unique. Also squalene and tocotrienol levels have been found to be very high. Amaranth has also got the ability to be popped and used in a variety of confections and bread.

Regarding industrial applications, these include uses of amaranth biomass for energy and development of unique applications of grain components. The tiny starch granules (1-3 microns) may be used as a talc replacement, an aerosol carrier for cosmetics or perhaps in biodegradable plastics (Saunders and Becker 1984). Approximately 7 % of the seed oil consists of a compound called squalene. This is an important ingredient in skin cosmetics and Preparation H as well as disc lubricants. Squalene is currently imported from Scandinavia and the Far East. It is obtained from whale and shark oils. The market for squalene is estimated to be over 60000 lbs / year (at $26.00 / lb-Lehmann 1990).

The potential impact of amaranth on human health is another area of increasing interest. Amaranth oils contain over 0.1 % tocotrienols, a class of vitamin E compounds which have been found to inhibit cholesterol (especially low density lipoprotein-LDL, the "bad" cholesterol) synthesis in laboratory animals. This content though, seemingly small, may be greater than that of many of our other common crops (Lehmann 1990). According to postulates of University of Illinois, tocotrienols are superior in the treatment of high serum cholesterol levels compared with corn oil placebo. Results of the study have shown that men and women with high serum cholesterol levels showed 20-31% decline in total serum cholesterol, and 28% decline in LDL when treated with 200mg of tocotrienols as compared with corn oil placebo controls (Science News 139:268, 4 / 91). The mechanisms for control of blood cholesterol via the use of cholesterol inhibitors (eg. tocotrienols) is distinct from the role of dietary fibres (eg. oat bran), since small quantities of inhibitors in the bloodstream could have an impact on serum cholesterol.

The species most widely used as vegetables are probably A. cruentus, A. dubius, and A. tricolor (Makus 1990). Amaranth greens (A. tricolor) contain about 28 % of proteins, 3.5 % lipids, 7 % fiber and 43 % carbohydrates, and respectable amounts of vitamins A and C (Makus 1990). In general, cooking or processing has an impact on the quality of green vegetables. Anti-nutritional compounds such as alkaloids, betacyanins, oxalic acid, and nitrates can be found in amaranth leafy material but this is also true for other leafy vegetables. Amaranth is a common vegetable in Africa and parts of Asia, while in the United States the markets are restricted to regions of the South and immigrant communities in large cities.

Although amaranth grain has been used in traditional foods in several cultures (Laidig 1981), it is not widely known to American consumers. This, however, is changing. Lehmann et al. (1990) estimated United States production of amaranth to be from 1.3-1.8 million pounds in 1988, on less than 5000 acres nationwide. There are several entrepreneurial groups in the US who have worked hard to develop markets and production stream for amaranth. The Amaranth Institute (Bricelyn, MN), a consortium of US growers, marketers, and researchers meets ones a year to share information and review latest advancements for the crop. This network has been important in the development of the crop to date and is likely to be important in the future.

Amaranth is higher priced than most commodity grains (prices have been 40-50 cents / lb to growers over the past several years), and so it is often included as an additive to a product rather than as the major ingredient. Teutonico and Knorr (1985) and Breene (1990) detailed a range of amaranth products: baking mixes; flours; breakfast cereals; snack foods; backed goods; canned products; pasta; sprouts; milled popped and extruded products; drinks infant formula; and animal feeds which are or can be made from amaranth. Several of these have been moderately successful and entered national markets and can often be found in health food sections of food outlets.

Lehmann (1990) outlined the factors of government support, price research, dependability of supply, pest control, and consumer familiarity to be important to the succesful commercialization of amaranth in the 1990s.

Amaranth is a vigorous, fast growing plant which produces abundant dry matter per unit time and area. This, in addition to its high protein content makes it a candidate for a forage crop; the primary role that amaranth could have as a forage is as a late-planted summer forage for northern climates or for drier areas. It is rather unlikely that amaranth could play the same role as alfalfa, with its perennial habit and high protein values. Amaranth forage and protein yield have been shown to be competitive with other summer annuals such as sorghum / sudan grasses. Amaranth has been known to ensile well, although high moisture content will require wilting (Stordahl, Unpublished).

Since amaranth is capable of producing floral buds from any leaf axil, it is a plant which is a candidate for a multiple-use crop, especially for farming systems which utilize animals. In environments which lack green fodder, but where farmers also require a cash crop or grain crop, amaranth plants could be cut for forage at an early stage, before significant floral growth. The daylength response in many lines causes flowering to occur early enough to produce a grain crop in addition to the forage crop. In some environments, this practice could aid in reducing plant height for ease of harvest, or lodging resistance.

Quinoa may be used either as a whole grain or ground into a flour. As a whole grain it may be incorporated into soups or cooked and served in a manner similar to rice. Its main use being in soups. Quinoa and Chenopodium pallidicaul (canihua) grains have no gluten and so they cannot be used alone for bread-making. Quinoa flour can be mixed with wheat flour in the preparation of bread and noodles, the proportion of quinoa flour varying between ten and forty per cent (Luna De la Fuente 1957). Weber (1978) stated that noodles have been made using 40 % quinoa flour without adversely affecting the appearance of other characteristics. It should be noted that quinoa was used in a composite flour blend for Bolivia (Bean 1981; Bean et al. 1982). Levels of 5 and 10 % quinoa in a wheat flour-quinoa blend caused a decrease in loaf volume (Bean 1981). Potassium bromate added at 20 or 40(mol mol-1 counteracted this volume decrease and produced bread similar to wheat bread with no dough additives. A number of quinoa recipes for cookies, chowder, croquettes and casseroles, have recently become available (Gorad 1986). Flour milled from germinated quinoa has also been used to reduce the viscosity of starchy foods. Supplementation with germinated quinoa flour may help to increase the palatability and the effective caloric density of food used for weaning children (Atwell et al. 1988). Flakes, similar to corn flakes, have also been prepared from quinoa (Tapia et al. 1979).

Corn grits-quinoa blends have been extruded successfully (Coulter 1989). Quinoa was blended with corn grits at levels of 10, 20 and 30 % and extruded under various conditions. The most acceptable products, he continued, were obtained at a 15 % initial moisture content and a 3:1 compression ratio of the extruder screw. Quinoa addition produced products which were higher in protein, fiber, ash and some amino acids than 100 % corn grits products. The products containing quinoa had a greater nitrogen solubility than the products containing only corn grits. Density, expansion and shear strength were lower for products containing greater levels of quinoa. Quinoa addition also produced a darker, less yellow product than corn grits alone.

Quinoa flour has given good results in feeding trials with chickens, pigs and ruminants. Stacks, chaff, gleanings, and bran are used to feed ruminants. The saponins obtained as a by-product in the processing of quinoa can be utilized in the preparation of products for photography, cosmetics (shampoo), and the pharmaceutical industry (synthetic hormones) (Tapia et al 1979).

1.3 BOTANICAL CHARACTERISTICS

1.3.1 Amaranthus cruentus aspect of the study.

TAXONOMY

This dicotylidonous plant is classified under the Amaranthaceae family and belongs to the genus Amaranthus (Szafer 1949, Hegi 1959, 1979). The family Amaranthaceae includes other genera like Achyranthes, Alternauthera and Celosia (Flora Europaea, Anonymous 1964). The genus Amaranthus is one of 65 genera in the family Amaranthaceae (Thames and Hudson 1966). The plants, in this family extensive, are mostly found in the tropical and sub-tropical zones of America and Africa (Thames and Hudson 1966; Hegi 1959; 1979; Nowak 1972). The family Amaranthaceae is a close relative of Chenopodaceae. Thames and Hudson (1966) particularly pointed out the similarity in the floral structure. They also noted the difference in the floral colour due to the coloured flowers of members of the Amaranthaceae family. The colour of the flowers enables insect-pollination. It is not easy to distinguish the two families in a natural way (Szafer 1919).

Willis (1973) stated that about 60 species make up the genus Amaranthus. However most of them are weeds. Weber (1990) identified A. spinosis, A. tuberculatus, A. retroflexus and A. rudis as weedy species. Domanska (1990) identified A. retroflexus as one of the most difficult to control. It is regarded as occupying third place in the hierarchy, in detrimentality to proper growth of cultivated crops. However the weedy species have some traits that render them useful. Brenner (1990) highlighted A. powellii A. bouchonii as weedy species involved in breeding for controlling shattering of seeds in mature plants.

There are also cultivated species in this family. A. cruentus, the species in the investigation at hand, has in the recent past proved to be very promising to researchers. This is largely due to the fact that unlike other species like A. tricolor, this species can be useful both as a vegetable as well as a grain crop.

Further down in taxonomic grouping, the species under investigation is known as Montana-3 (MT-3) developed at Montana in the United States and released in March 1988. The MT-3 grain amaranth is itself a selection from RRC-1041 developed by the New Crops Department of the Rodale Research Center (RRC) at Kutztown, PA, from a single plant selection RRC-78S-1015 (Kauffman 1981). The line MT-3 has been registered under the name Amont (Montana Amaranthus).

MORPHOLOGY

The family Amaranthaceae has got different forms of aerial growth. There are members of this family that are branched while others are devoid of branches. Other members of the family are creeping while others are upright in growth. There are also colour differences noted. The leaves and stems display colours ranging from red to green.

The colour of the seeds also differ among the members. There are white, yellow, brown to totally black seeds (Amaranth-Information, Annonymous 1989). The grain types have white seeds while the vegetable types (as well as those used to extract red dye) usually are dark seeded. Amaranth seeds are very small; 1000-3000 seeds per gram are common. Although selections have been made over the years for pale seeds (the wild species all have black seeds), large inflorescence, and more seeds per plant, there has apparently been little selection for large seed size (NAS 1984).

The plants are mostly monocious but sometimes dioecious. The members of this family are mostly annuals and seldom perennials. The leaf arrangement is either opposite or alternate. The leaves can be with or without a leaf stalk. They are noted for lack of leaf bract. The members have singly occurring inflorescence. The flowers exhibit monoecism or dioecism. The ovaries are hypogynous and very seldom perigynous. The flowers are usually in a thick cluster of ear (Hegi 1959, 1979; McGregor 1970; Malean and Rivimey-Cook 1951).

The grain amaranth species belong to the genus Amaranthus and are characterized by monoecious compound inflorescence and five merous flowers with circumscissile utricles. The basic units of the inflorescence are little dichasial cymes, usually called glomerules, each ordinarily consisting of an initial staminate flower and an indefinite number of female flowers. The glomerules are crowded on a leafless axis to form complex inflorescence, technically thyres, which are generally called spikes. In all the grain species, each flower is subtended by a sharp-pointed bract. The perianth consists of five free "tepels" the male flowers characteristically have five stamens, the female a single circumscissle utricle.

The main axis of the inflorescence is usually branched. The length and number of these branches and their angle with the main axis determine the shape of the inflorescence. The cluster of individual flowers develop along this axis in an alternate fashion. The first flower is terminal on the branch and at its base two branches develop the second and the third flowers. Each of these flowers in turn is terminal and at its base develop the next two flowers. This process continues until all the available space is occupied. Development is usually very symmetrical up to the third or fourth series of flowers. At this time the setting of the first seed usually shows down growth and upsets the symmetry. Unpollinated clusters may develop an exceptionally large number of flowers. The monoecious species, exhibit two types of arrangements of the staminate and pistillate flowers. These types are important because of their different breeding behaviour. In the first type, the first flower of each flower cluster is a staminate flower and all the secondary ones are pistillate. There is only one staminate flower, in each flower cluster of the inflorescence and this abscesses soon shedding pollen. All species except A. spinosus, belong to this group. In the second type, all the flowers develop only in the axis of the branches and at the base of the terminal inflorescence, while the clusters of staminate flowers are born terminally on the main axis and lateral branches. The species A. spinosus, belongs to this type (cited by Josi and Rana 1991).

A. cruentus L. has leaves with long leaf stalks. They are rhomboid to egg-like in shape, both ends are drawn to sharp bony tips. The flowers are collected in thick clusters. Leafless clusters form sedentary lids on the tips of stems, sometimes bottom clusters at the base have leaves (Amaranth information, Annonymous 1989).

1.3.2 Chenopodium quinoa aspect of study

TAXONOMY

The plant belongs to the Glasswort family, Chenopodiaceae. Wilson (1990) stated that over 120 species have been found within the genus Chenopodium. Chenopodium quinoa is not the only chenopod of importance to mankind, a very similar plant huauzontle (C. berlandieri subsp. nuttalliae), is cultivated in Mexico as a vegetable and for grain, and a low-growing species, canihua (C. pallidicaule), is grown for forage and grain on the Altiplano around lake Titicaca. In the Himalayas, plants classified as C. album are cultivated for grain (Partap and Kapoor 1984). The adaptability to cold, dry climates, seed processing similarity to rice and excellent nutritional qualities make quinoa a crop of considerable value to highland areas around the world which are currently limited as far as crop diversity and nutritional value are concerned. Development of the other Chenopodium species in the United States (Wilson 1981), the Himalayas (Partao and Kapoor 1985), Mexico (Risi and Galway 1989) and Denmark (Renfrew 1973) illustrates a diverse appreciation for this genus. Even the weedy relatives, C. album and C. berlanderii in the United States and around the world have been utilized as food during times of starvation.

MORPHOLOGY

The plant is a summer annual leaf-rich herb. It varies in height from 0.7 to 3.0 m and has an upright stem that may be branched or unbranched. It is stout between 0.5-2.5 cm in diameter. It may have grooves or simply smooth, oval to spherical. It bears alternate highly polymorphic leaves. The fruit they produce has a pale yellowish colour with an occasional tinge of magenta pigment. The grain is conical, cylindrical, or ellipsoidal in shape and it varies in diameter from 1.8-2.6 mm. The weight of 1000 seeds (TSW) is 3.0 g (KVL O188 variety). The grain is protected by a perianth consisting of loosely adhering cells, which can easily be removed by washing, a pericarp and two seed coat layers. It is the seed coat that contains the bitter saponins. A thin episperm covers the curved embryo (Coulter and Lorenz 1990). The flowers are usually monoecious cleistogamous, inflorescence 20-30 cm long. Cross pollination is between 2-9%, which means inbreeding is predominant.

1.4 GENETICS AND BREEDING

1.4.1 Amaranthus cruentus aspect of study

The majority of plant characters is polygenically inherited with relatively large numbers of genes exerting greater or lesser effect. In the Amaranthus species the environment modifies the genes in the expression of most of the characters. Field evaluation screening and study of the genetic variation for a set of morpho-agronomic attributes showed a wide range of variation in grain amaranth (cited by Joshi and Rana 1991). Among the characters studied, thousand seed weight, protein percentage, seed yield, plant height and inflorescence length had shown high genotypic coefficient of variation, high heritability and high genetic advancement indicating that these are more important traits for selection or breeding (Joshi 1986).

Genetic variation in landraces was studied by Jain (1985) using qualitative markers, quantitative traits as well as allozyme variation. The New World collection varied in the amounts of genetic variation between regions and possibly between species. Most landraces seem to be highly homozygous and carry a significant amount of variation for quantitative traits such as plant height, branching, flowering time, head length and harvest index. Accessions from India rather suprisingly, showed no or little allozyme variation within and among populations, but seemed to be highly variable from a morphological point of view.

Ten landrace populations from two states of India were evaluated in the greenhouse by Vaidya (1984) for genetic variation of qualitative characters. The qualitative characters studied were: seedling colour, leaf margin colour, leaf texture, leaf margin hairiness, leaf marker and inflorescence colour. These characters segregated in several families of the populations. Seedling colour difference (red Vs green) was simply inherited while the ‘V’ mark leaf marker was controlled by two epistatic genes.

1.4.2 Chenopodium quinoa aspect of study

Genetic make-up is very important in screening for particular characteristics, selection, or routine field evaluation. In all these cases the allowance for genetic interaction in the expression of character traits should be unlimited. Proof of this attribute in C. quinoa is manifested in results of cytological studies by Crawford (1973) who identified diploid and tetraploid species. Furthermore hexaploid species of C. album that are smooth-fruited have been identified by (Cole 1962; Keener 1970; Uotila 1978). The fact that these smooth-fruited C. album complex appears to be essentially European in origin was expressed (Wahl 1952, 1953; Aellen 1960).

The species of the genus Chenopodium are generally self-compatible and anemophilous. Flowers are small and often clustered into dense bracteate glomerules. These makes artificial hybridization, which often involves emasculation and cross-pollination inapplicable. However male-sterile strains of the alveolate-fruited domesticate of C. quinoa developed by Simmonds (1971), indicated that anther abortion is a simple recessive characteristic that can be inherited cytoplasmically. Another hybridization program involved the use of egg parents with no history of male-sterility in investigations, by Wilson (1980), on photoperiodic response.

A screening study by Risi and Galwey (1988) involving 294 accessions of quinoa evaluated at Cambridge, England, registered the rich admixture of genetic make-up in the expression of character traits. These researchers were screening for a break crop for arable agriculture in temperate latitudes. The ideotype of short, unbranched, early maturing plant with a compact inflorescence and a high harvest index, large light-coloured seed with a low saponin content, were postulated for in chilean accessions.

1.5 CHEMICAL COMPOSITION

1.5.1 Amaranthus cruentus aspect of study.

Saunders and Becker (1983) compared results of nutrient composition analysis and other feeding values of selected leafy vegetables to those of amaranth. The vegetables involved were Spinach, Basella and Chard. Amaranth’s 36 Kilo calories of energy per 100g of edible portion was the highest compared with those of the other vegetables. The dry matter, carbohydrates, protein and ash contents of 13.1, 6.5, 3.5 and 2.6 g/100g respectively of edible portion of amaranth were also found to be the highest. They also reported the results of phosphorus, potassium, calcium, chlorophyll, vitamin C and carotene as 67, 411, 267, 150, 105, and 10.1 mg/100g respectively for amaranth. It should be noted that, except for potassium and carotene, the afore-mentioned values of amaranth were the highest compared with the other vegetables. It should be further noted that the values of potassium and carotene although not the highest were however not very disimilar to the highest.

Bressani et al. (1987a) reported the mineral content of four grain amaranth i.e. A. caudatus, A. hybrydus, A. cruentus and A. hypochondriacus in mg/g dry weight basis (d.w.b). The values of phosphorus, potassium, calcium, magnesium, sodium, iron, copper, manganese and zinc they reported as 556, 525, 242, 344, 25, 26, 1.69, 3.4 and 4.2 respectively for A. cruentus. It should be observed that except for iron, A. cruentus was found to have higher or comparable values with the other species.

The elevated crude protein level of both vegetable and grain amaranth with respect to the level considered adequate is among the reasons that amaranth has recently been decleared an under exploited crop with promising economic value by the National Academy of Sciences in the United States (NAS, 1975, 1984).

Food Technology of April (1985) reported tabulated results of nutrient elements. The vegetable amaranth and the grain amaranth had 20.9-33.0% and 13.2-17.6% CP respectively. These are elevated with respect to the 1.5% N (9.4% CP) level considered adequate in table 8.

As a whole amaranth compares favourably to other cultivated crops. According to Amaranth Brochure (1991) the crude protein content of Amaranthus species is about 16% of DM. This compares favourably to the values of crops like wheat 13.3 %, corn 7.8 %, rice 7.6 % and oat 14.2 % reported by the same publication.

The amino acid composition of amaranth is very complex and often high in essential amino acids for the normal human diet and forage production (Tayler 1981; Lehman, 1989; Czamieliwa, 1989; Nalborczyk, 1991).

Recent CIMMYT progress in producing quality protein maize (QPM) suggests that the protein level of corn can also be modified to produce superior human and animal foods. However, if one considers that various amaranth/cereal blends may accomplish the same goal, much more concern is laid on the improvement arguement. For example Morale et al. (1988) proposed that if toasted amaranth is blended in a 1 : 8 ratio, it could provide most of the protein and fat needs of young children. According to a Rodale press report RRC 11/87 (1987), it can be deduced that using a mixture of a few grams of amaranth and cereal is enough to satisfy the FAO/WHO daily recommendation of 2.94g amino acid /100g of grain for leucine. Leucine is the limiting essential amino acid in amaranth. A similar mixture can be used to satisfy the recommendation for methionine/cystine reported in the same issue of RRC 11/87. Simply this is a less expensive way to meet nutrient level requirements than trying to raise the 0.19-0.265g amino acid /100g of corn as suggested by CIMMYT.

According to Saunders and Becker (1983) A. cruentus had the highest value 17.8 %CP with a cross between A. cruentus and A. hypochondriacus as runner-up with a value of 17.4 %CP, while A. caudatus and A. hypochondriacus had values of 15.8 %CP and15.6 %CP respectively.

In table 9 Tayler 1981; Lehman 1989; Czamieliwa 1989; Nalborczyk 1991, have shown that Amaranthus cruentus might compare favourably to A. caudatus and A. hypochondriacus as it has higher amounts of amino acids including essential exogenous ones like lysine, which favours the possibility of synthesis of more different types of protein.

The fatty content percentage was reported by these workers as 7.8, 8.0, 8.1 and 6.1, the crude fibre was reported as being 4.4, 4.1, 3.2 and 5.0, while the ash content was reported as 3.3, 3.0, 3.2 and 3.3 for A. cruentus, the cross between A. cruentus and A. hypochondriacus, A. caudatus and A. hypochodriacus, respectively.

It is also important to note that the high protein content of amaranth is not at the expense of the fat content. The following fat content in percentages has been reported : 7.2, 2.1, 4.4, 4.4, 5.1, 2.1, 1.8, 3.4 and 1.9 for amaranth, barley, corn, (dent) millet, oats, rice (with hulls), rye, sorghum and wheat (hard) respectively (Garcia et al. 1987; National Academy of Science 1969).

1.5.2 Chenopodium quinoa aspect of study.

A breakdown of the nutritional value of C. quinoa is found on table 11. Some of the micronutrients like Mn and Zn are found to have sub-optimal levels. Zinc, however had optimal levels in C. quinoa white and C. pallidicaule. Iron and copper also investigated in the cited study had optimal levels in all four species.

The comparison between mineral nutrient contents showed that in general some antagonism does exist, between the macronutrients potassium and calcium. Leggett and Egli (1980) highlighted this antagonism by stating that calcium and magnesium percentages decrease concomitantly with increased potassium uptake. Apart from calcium that was deficient in C. quinoa white and C. pallidicaule all the other macronutrients were considered sufficient in all four species of Chenopodium in Table 10.

The nutritional value of quinoa has been known for a long time to be superior to traditional cereals and is, in fact, superior to milk solids in feeding trials (White et al 1955). Protein content ranges from 10 to 18% with a fats content of 4.1 to 8.1%. Starch, ash and crude fibre average content is 60.1, 4.2 and 3.4%, respectively (De Bruin 1964, Ballon pers. commun.). Table 10 compares four Chenopodium species.

Considering protein content it is noteworthy that C. quinoa has a few percentage points higher than that of most cereal species, this is shown on Table 12. The protein has been found to have a better balanced amino acid composition, having a higher proportion of lysine and essential sulphur-bearing amino acids such as cystine and methionine. Notwithstanding the high level of protein and mineral nutrients of quinoa, the presence of saponins is a major setback in the use of the seeds for nutritional purposes.

Saponins are a class of bitter-tasting glycosides in which the aglycone portion (the sapogenin) is a steroid alcohol. Saponins are soluble in water characteristically producing a foam, hence their name (Blackmore and Tootill 1984). It is known that quinoa contains a number of structurally diverse saponins including the aglycones, oleanolic acid and hederagenin (Burnouf-Radosevich et al 1985). Mizui et al (1988) have identified six such saponins from quinoa bran including those containing phytolaccagenic acid.

Quinoa can be classified according to its saponin concentration as either “Sweet” (saponin free or having less than 0.11% saponin on a fresh weight basis) or “bitter” (containing more than 0.11% saponins) (Koziol 1990b). Once saponin is removed, protein quality was unaffected. Amino acid balance was virtually the same regardless of saponin content of the seed (Burnouf-Radossevich et al, 1983). If C. quinoa is intended for human use, the saponins must be removed before processing and/or cooking. Junge (1973) has described the use of alkaline washing or dry scouring for this purpose whilst other workers have used roller-milling (Amaya-Farfan et al 1978) and abrasive dehulling (Reichert et al 1984, 1986b). Price et al (1987) has described the effectiveness of these three methods of saponin removal by exploiting the foaming, antifungal and haemolytic properties of saponins. It was also stated by Galwey et al (1990) that genetic, agronomic and environmental factors as well as processing can considerably affect saponin contents.

Accessions from Ilave market, Puno, which are fairly early maturing, and would therefore be attractive sources of genes for low saponin content, have the disadvantage of small, strongly pigmented seeds. On the other hand low saponin accessions with low saponin content from the Andean valleys often have large white seeds but are tall and late maturing. The authors however warned that some of the relationships between attributes are weak.

1.6 PHYSIOLOGY

1.6.1 Amaranthus cruentus aspect of the study.

The two species under investigation, belong to two different photosynthetic pathways. A. cruentus belongs to the NAD-malic enzyme C4 pathway while C. quinoa belongs to the C3 pathway. The carbon dioxide fixation classified as C4 includes a wide range of plants. Enlisted are warm-season grasses such as corn, sorghum sudangrass, sugarcane, millets, bermudagrass and warm-season prairie grasses. Among dicotyledonous species identified in this carbon fixation pathway are Amaranthus spp., and pigweed. This pathway incorporates CO2 using phosphoenol pyruvate (PEP) carboxylase. The ATP which is produced in photophosphorylation is used to convert pyruvate to PEP. The PEP, a three-carbon molecule, is carboxylated to three four-carbon acids (oxaloacetate, malate and aspartate). These compounds are translocated to vascular sheath cells where fixated CO2 , by PEP carboxylase, is released and further added to RuBP by ribulose bis-phosphate (RuBP) carboxylase/ oxygenase. Where the change to pyruvate, causes a carbon to be released that is further added to RuBP by ribulose bis-phosphate (RuBP) carboxylase/ oxygenase.

The PEP carboxylase has greater affinity for CO2 than RuBP carboxylase/ oxygenase, so it can operate more efficiently at low CO2 concentrations. Species with C4 fixation, generally have higher photosynthetic rates than do C3 species, especially at high light intensities. Among the reasons identified is the non-significance of photorespiration in C4 species which is partly due to movement of the 4-carbon acids into the vascular sheath cells, hence elevating the concentration of CO2. The elevated concentration of this substrate favours the RuBP carboxylase reaction over the RuBP oxygenase. Equally important in the non-significance of photorespiration is that loss of CO2 is prevented in the mesophyll by PEP (Goldsworthy 1970).

1.6.2 Chenopodium quinoa aspects of the study.

The C3 species include cool-season cereals and grasses like wheat, oats, barley, rice, rye, bluegrass, fescue and bromegrass. Among dicots the list includes most temperate species like C. quinoa, legumes, cotton, sugar beets, flax, tobacco, potatoes etc. The CO2 fixation portion of the Calvin cycle is catalysed only by RuBP carboxylase. The ATP produced during photophosphorylation is used to convert ribulose-5-phosphate to RuBP. After CO2 fixation ATP along with reduced nucleotides from the light process change 3-phosphoglyceric acid (3-PGA) to 3-phosphoglyceraldehyde (3-Pgald).

Photoperiodic effects

Eze (1987) observed the effect of five levels of daylight on amaranth and stated that the total plant fresh weight was greatest in full light (as were both the fresh and dry weight of the roots). Leaf area was greatest at 50% light, diminishing with increasing shade. The percentage flowering and number of branches were greatest and senescence was most rapid in full light. Stem weight ratio varied only slightly between treatments, they concluded that a decrease in irradiance is accompanied by a decrease in the root weight ratio, whereas the leaf weight ratio increases. The contents of total carbohydrate, ascorbic acid and chlorophyll a and b per unit dry weight of leaf tissue and the chlorophyll stability index were higher at higher light intensities. Protein accumulation was best at 70% light.

Fuller (1949) stated that A. cruentus originating from Nigeria is an obligatory long-day plant which flowers and yield only when the day is long. While Allard and Garner (1949) described A. hybridus L. and Amaranthus Sp. Dreer Sunrise as day neutral plants (DNP). These workers further stated that all other Amaranthus species examined in later studies behave as obligatory or facultative (short day) SD plants. They also observed that A. caudatus L. in general is facultative but the variety albiflorus is obligatory. They also stated that A. retroflexus L. and A. graecizans L. are facultative while A. tricolor L. is obligatory.

Fuller (1949) working with seed material from Bolivia, found out that C. quinoa is an indeterminate of day neutral species. The day length sensitivity of C. quinoa was also reported by other authors (Cardenas 1949; Leon 1964; Simmonds 1976). Fuller however failed to find any studies concerning the photoperiodic requirements of canihua (Chenopodium pallidicaule, Aellen).

The degree of the sensitivity of C. quinoa to day length can be found in the data of Risi and Galwey (1991). They studied two varieties of C. quinoa and they showed that Baer flowered earlier than Blanca de Junin. Baer has the shorter vegetative period when both varieties are grown in their native areas, and moreover it is possible that Blanca, which originates from low latitudes, is inhibited from flowering by long days.

The Chilean cultivars are known to perform well in European daylength where the vegetative period usually reaches 150 days. On the other hand with cultivars from Bolivia one observed robust vegetative growth and longer vegetative period. Ritter (1985), Risi and Galwey (1989) explained this phenomenon as nearness of Bolivia to the equator which means maximum variation in the daylength is several times less than in Europe. In general the crop is considered as photoperiodically neutral. Substantiation of their claim is manifested in the origin of the seeds, that is global in setting.

Carmen (1984) investigated acclimatisation of quinoa and canihua (C. pallidicaule, Aellen) to Finland. The Finish experiment showed that about fifty of the quinoa ecotypes and thirty-five canihua ecotypes produced mature seeds in Jokioinen, one of the experimental sites. The total number of ecotypes of quinoa tested was seventy-six while that of canihua was thirty-five. The Finish experience provides some evidence of the day length neutrality of C. quinoa as a result of its location. The disparity in the day length within the cause of one year is enormous compared with locations near the equator.

1.7 PHOTOASSIMILATE DISTRIBUTION

Plants allocate the carbon (C) they fix from the atmosphere to meet the demands associated with their life: they need energy to grow and maintain their tissues and organs, they need to reproduce or extend their life in some fashion, and they need reserves for unfavourable periods.

Fluxes of carbon which are involved in the distribution within (partitioning) and between (allocation) plant organs change predictably throughout the life of a plant (Dickson and Isebrands 1993). Chapin et al. (1990) identified four time intervals over which C supply alternates between surplus and deficits: day to night, good to poor environmental conditions, summer to winter, and vegetative to reproductive states.

A plant’s ability to accumulate assimilated carbon is a function of its photosynthetic capacity and pattern of carbon distribution among its parts, both of which appear to be genetically determined (Gifford et al. 1984).

Allocation of recently fixed carbon involves a number of biochemical pathways and compartmentation steps. In a mature leaf, most of these processes support the export of assimilated carbon and its distribution among sinks (Geiger and Bestman 1990).

Balanced allocation of recently fixed carbon between export and reserves supplies carbon compounds for maintaining both immediate and delayed phloem translocation (Fondy et al. 1989; Servaites et al. 1989a, b), thereby providing a vehicle of communication among regions of the plants.

In some cases allocation also provides compounds, such as growth regulators or metabolites, that communicate information related to the presence of the stress. In water-stressed plants, cytokinin or abscisic acid (ABA) may serve this purpose. Allocation can also serve the purpose of providing the carbon needed for a stress response. For instance, when the related water content of an exporting leaf falls, carbon may be allocated for synthesis of osmotic agents in the leaf (Fox and Geiger 1986).

Allocation supports long-term reserves. which in turn supply carbon that can allow a plant to respond to stress during a given developmental stage, at the begining of the next season’s growth, or on germination of the next generation of plants. Daily and long-term carbon reserves enable plants to acclimate to stress by maintaining overall fitness, maintaining phloem translocation by way of communication and integration, and, especially, by serving as a buffer in the event of a stress that slows or stops photosynthesis. Allocation also involves buffer reserves. Carbon stores, located in source organs, along the translocation path, and in various sinks, serve as buffers by providing a temporary supply of carbon that can be mobilized whenever the supply of photoassimilated carbon becomes limited. This is to the extent that these reserves are available for mobilization. They can negate the effects of rapid decreases in carbon supply. For instance, when export from a leaf is drastically slowed down by cooling a region of stem or petiole, import is maintained by mobilization of buffer reserves (Swanson and Geiger 1967; Minchin and Thorpe 1987).

Allocation also draws from reserve carbon. Reserve carbon is needed daily, even, in the absence of stress, for growth and metabolism. A variety of adaptations enable plants to maintain a steady carbon supply for distribution during the daily dark period as well as to supplement the transition hours from day to night and night to day. Allocation of newly fixed carbon to daily reserves within exporting leaves maintains this supply. Some plants, including barley (Gordon et al. 1982), spinach (Robinson 1984) and sugar beet (Fondy et al. 1989; Servaites et al. 1989a) store sucrose throughout much of the day.

In nature this capacity also depends on the plant’s ability to maintain dry matter accumulation in the face of an ever-present variety of stresses. Most plants fall far short of their full genetic potential for productivity because of environmental stress. For a variety of crops under field conditions, even agricultural yields are only 12 to 30% of record yields (Boyer 1982). The ever-present stress phenomena, which in nature are frequently made-up of different stresses lead to a search for an understanding of the ways in which allocation integrates stress responses in different plants. Such an understanding leads to recognition, and might preserve the genetic diversity needed for acclimation to stress in native plants.

There are two types of acclimation to the variety of stresses in nature. The short term direct responses involve the stress-induced change in the system input or output to cause a signal which in turn causes the system to initiate an acclimation response. For instance, atmospheric humidity and transpiration rates are inputs for the system enabling the plant to achieve and maintain a balanced water status and avoid desiccation (Schulze 1986). However, direct responses are unlikely to enable the plant withstand a persistent stress. Acclimation of plants to the events initiated by stress via responses mediated through altered gene expression and biochemistry are those that have a meaning in counteracting a persistent stress (Queiroz 1983; Geiger 1986). The changed system output serves as a signal that sets in motion a mechanism mediated by changes in the system itself. Changes in gene expression through gene activation, transcription, and translation can lead to new plant responses (Sachs and Ho 1986). New structural or physiological characteristics create an altered system that restores the original output, even though the stress-induced changes in the output are not reversed. The successful response creates a plant with changed metabolism, biochemistry, or both, that often can function well even though the stress persists. Under water stress, for example, initiation of more extensive root growth can increase water uptake so that turgor is restored despite high transpiration in the dry air (Meyer and Boyer 1981). In view of this though partitioning plays a major role within the cells of the organs by determining what portion of the newly assimilated carbon should be stored as starch or as sucrose in the vacuoles, distribution between organs by way of allocation has far-reaching aims in enabling the plant to acclimate.

There are anatomical differences which show that the leaf anatomy of the C4 fixation pathway is called the Kranz anatomy. The structure of the leaf in this anatomy reveals sheath cells which have chloroplasts with less developed grana than in mesophyll cell chloroplasts. These chloroplasts are also capable of storing starch unlike those in the mesophyll layer, because the Calvin cycle is operative in them. The C3 species are lacking in specialized sheath cells.

Furthermore differences in adaptation occur for species with different CO2 fixation mechanisms: C3 species are adapted to cool and moist to hot and moist conditions while C4 species are adapted to hot, dry, or moist conditions.

Large differences in water use efficiency (WUE) occur when species are categorized by CO2 fixation pathway. It is now accepted that the WUE of C4 species is generally higher than that of C3 species (Downes 1969; Bjorkman 1971; Brown and Simmons 1979). Differences between C3 and C4 species increase as the temperature rises from 20 to 35oC (Bjorkman 1971).

Therefore response to stress by way of distribution or normal distribution patterns of photoassimilates have to be investigated constantly. Hence the justification of the research at hand.

1.8 AGRONOMIC PRACTICES

1.8.1 Amaranthus cruentus aspect of study

Field preparation and sowing

Under Polish conditions most weeds germinate in early spring so it is possible to speed-up their emergence and then destroy them by frequent harrowing. It is however noteworthy that heavy equipment that destroy the soil structure or cause extreme drying of the top soil layer should be avoided. Moisture is one of the most important critical factors during germination dictating either delayance or uneven emergence. The field must be well levelled and two to three harrowings are sufficient for sowing of amaranth seed.

Amaranth is generally sown in the first or second week of June, after the first shower. Johnson (1990) stated that in the US there is often no penalty for late planting (as there is with corn). In North Dakota, high yields are produced from mid-June plantings. In most temperate countries sowing is recommended after the last frost in spring. Traditionally the seeds are broadcasted but better crop stand is achieved if seeding is done in rows. The depth of sowing should be less than 2 cm, as a result of very small grain size.

A row spacing of 50 cm or 20 cm is usually recommended. The higher row spacing is frequently used where a lot of weeding is anticipated and where harvesting is done manually. Where harvesting is mechanically done the lower row spacing is usually recommended. In the case of the higher row spacing, allowing 20 cm between plants and using the recommended seed rating of 1.5-2.0 kg/ha will give a good grain yield. The lower row spacing usually requires less than 20 cm between plants with the crops more even in growth and less branching, which favours mechanical harvesting. The seed rating of amaranth is based on the thousand seed weight (TSW) which is about 0.7 g as compared to that of mustard which is about 5 g (Johnson et al. 1990). The recommended plant rate per square metre is 18-30 (Josi and Rana 1991).

Fertilizer requirement

Field observations indicate that amaranth grows well on soil containing widely varying level of soil nutrients. This is also substantiated in Amaranth Information (1988) by stating that amaranth, while not dictating any prefixed soil requirement for normal growth requires a good soil well supplied with mineral nutrients. However species like A. tricolor have been proved to be non-susceptible to saline soils (Magomiedow 1989; Buren, Vavilov 1992) and also tolerant to high levels of aluminium (Foy and Campbell 1981; Mahus 1988). Anyway, the level of tolerance has a limit as verified by a modified mass selection program used by Campbell and Foy (1987) while screening four grain amaranth populations (R101 and R103 A. hypochondriacus, R123 A. cruentus, and R125 A. hybridus) for tolerance to aluminium in pH 4.8. All four were found intolerant to high levels of aluminium. The same authors also published results which showed that further breeding is necessary before adequate levels of aluminium tolerance can be reached. The same workers also stated that tolerance to high aluminium levels may be inversely or directly related to desirable agronomic traits as well as inherited independently.

Initial studies carried out in Pennsylvania (Rodale Research Centre) showed that young grain amaranth grew taller with fertilizer application, but the grain yield did not justify the fertilizer application. Vegetable amaranth on the other hand, requires high soil fertility (especially for potasium and nitrogen).

Bressani et al. (1987) stated that A. cruentus ecotypes from U.S.A. and Guatemala, A. hypochondriacus from U.S.A. and A. caudatus from Peru were treated with 12-24-12 NPK fertilizer at three levels 0, 30, and 60 or 90 kg. Fertilizer had no significant effect on yield, but increased the seed protein content in the two lowest yielding ecotypes. The effect on seed fat content was inconsistent.

Breeders from Mexico and also Weber (1990) recommended the following fertilizer level N90-100, P 60-70, K 60-70. They recommended that fertilizer application should be split into two stages: an initial application before sowing and at the stage of maximum intensive growth. Other workers reported that vegetable and forage varieties are prone to benefit a lot from nitrogen fertilizers. They however warned that excessive nitrogen can lead to the accumulation of toxic concentrations in the plant for both man and animals (Senft 1979; Magomiedow 1987). Oke (1979) and Mustafa (1984) recommended the use of organic fertilizers.

Water requirement

In order to germinate and establish roots, amaranth seeds require well-moistened soil, but once seedlings are established, grain amaranth does cope with limited water. It has been shown to grow well under dry warm conditions. On the other hand vegetable amaranth requires moisture throughout the growing season. Grain amaranth has been grown in dry areas receiving as little as 200 mm of annual precipitation, while vegetable amaranth is usually grown in areas receiving 3000 mm of annual rainfall. Indeed, in West Africa vegetable amaranth production continues even during the torrential rainy season (Amaranth Information 1988).

Pests and diseases

According to Weber et al. (1990) the most pervasive damaging insect to date occuring on amaranth seems to be Lygus, sometimes called tarnished plant bug (TPB) and its economic threshold for damage was found. Wilson (1989) has summarized some insect feeding studies on amaranth, including tests on the tarnished plant bug Lygus lineolaris Palisot de Beauvois the fall army worm (Spodoptera frugiperda J. E. Smith), the cabbage looper (Tri choplusia Ni Hubner), the corn earworm (Heliothis zea Boddie), and the cowpea aphid (Aphis craccavora Koch.). It should result in breeding for insect resistance and implementation of integrated pest management. Pesticides have not been certified for use on amaranth. Yet ironically, given consumer concern over pesticide contamination of foodstuffs, lack of pesticide certification may encourage introduction of the crop.

The cosmopolitan Lygus lineolarus bug (cabbage looper) has been recorded on 32 host crops. Lygus bug damages amaranth by feeding on the meristematic tissue, developing floral buds, immature blossoms and developing embryo. The feeding causes localised wilting, tissue necrosis, abscission of fruits, morphological deformation of fruits and seeds and also altered vegetative growth. The damage has been caused by piercing the developing plant organ and sucking out the juices. Other economically important pests are leaf miners, spider mites and stem weevil which is a major pest of amaranth whose grubs damage foliage and roots hence causing the plant to wilt. Stem borers (Lixus truncatucus) are also a serious problem for the early developing crop in Asia and Africa causing lodging in plants. During rainy seasons leaf rotters also cause considerable damage. Other pests of the crop are Hypolixus nubilous (Egypt), Rhachi creagra (Costarica), Chrotogonus spp (Pakistan), Hyphurus spp (India), Geocoris spp (California), Thysanoptera spp(Hawaii), Haplopthrips longisetosus (India), Diabnotica barberi and Spodoptera exigna. Meloidogyne incognita, (chitwood) root knot nematodes are serious pests of celosia that also slightly affect Amaranthus species.

In South Mexico amaranth has also been used as a guard crop. Weedy amaranth species are planted alongside corn fields because the pests that usually attack corn prefer amaranth to corn leaving the corn alone (RRC 1983).

Pandy et al. (1985) while studying the leaf surface mycoflora of Amaranthus paniculatus found minor occurrence of Fusarium oxysporum and Nectria cinnabarina where as other species among them Alternaria alternata, A. amaranthi, Phoma glomerata, P. hiburnica, Phyllostica spp (leaf spot), Asperigillus luchunsis and Rhizoctonia species were commonly isolated. Furthermore soil fungus, damping off, leaf blight, white rust mycoplasma and virus have been identified as the serious diseases of amaranth in India.

Sealy et al. (1988) screened a total of 126 accessions of species and cultivars of Amaranthus for resistance against Pythium myriotylum. They recommended that accessions exhibiting weighted percentage mortality of less than 20% be selected for use in breeding programs against damping off disease. Bialoskorski et al. (1982) also observed Pythium aphamidermatum damaging amaranth crop in Brazil. McLean and Roy (1988) reported Colletotrichum domatium damaging Amaranthus hybridus plant in Mississippi, USA. In India a casual organism Xanthomonas amaranthicola a bacterial leaf spot disease of amaranth has been reported (Reddy et al. 1980).

Sharma et al. (1981) and Naseema et al. (1983) reported Aspergillus flavuus, A. niger and Rhizopus stolonifer as the major storage fungi of amaranth crop in India. According to Sharma and Chowfla (1987) a mosaic disease caused by a strain of cucumber mosaic virus occured in Amaranthus caudatus. Sammons and Barnett (1987) reported that tobacco ring spot virus damaged Amaranthus hybridus in California, USA.

Harvest

In the case of grain amaranth it is recommended that combine harvesting be differed until there is a killing frost for temperate regions (Putnam 1991). This is to prevent eventual shattering of harvested grain. In the tropical regions it is advisable to harvest in the morning when the plants have optimum moisture as a result of elevated night relative humidity. This is also a measure recommended to prevent shattering of seeds during harvest.

Mechanical harvesting is enhanced by the relative heavier weight of the grain to the husk (Amaranth Information, 1989). Varadinov et al. (1989) stated that grain amaranth inflorescence is about 50% of the whole plant. In the case of forage amaranth about 20% is leaves, 30% is stem, while 45% is inflorescence.

Yield

Czernow and Zemlonoj (1991) stated that it is possible to obtain 100 tons per hectare of leafy vegetable with a protein content of 5 tons which is even higher than that of soya.

Maximum grain yield of 1.8 tons per hectare has been reported from experimental fields of Pensylvania while in California twice as much has been reported. From the Himalayas where C. hypochondriacus is the main grain amaranth a 3.0 ton per hectare has been reported (Amaranth Information 1989).

Bressani et al. (1986) reported that out of 14 selections of four Amaranthus species studied, six yielded over 0.3 kg m-2 and three below 0.1 Kg m-2. Grain size varied from 1.55 to 2.14 mm and seed weight from 0.46 to 1.18 mg per seed. In the variation of yield between selections, A. cruentus contributed the least. Plant height at flowering and yield were not found to be related while some relationship was found between plant height at harvest and yield. The best yielding cultivar was A. hypochondriacus (A-718) with 4091 kg/ha.

Crop rotation

It has been reported that amaranth does not leave any harmful allelopathic effects for the next crop (Risi and Galwey 1984). Indeed where a large quantity of cereals is involved amaranth can replace rye and wheat. In USA the most popular crop rotation is wheat-amaranth-wheat. It is therefore effectively a break crop. A break crop should be able to satisfy the important reason of avoiding diseases and pests of a particular crop, while the change should not be at the expense of the soil structure and its chemical properties. Amaranth has not been found lacking in these properties.

Amaranth as a weed

Until now there are no chemical means of weed control especially post-emergent ones on amaranth plantations. This may be partly due to the fact that most preparations are based on controlling amaranth as a weed. Species like A. viridus, A. spinosis, and A. hybridus are persistent weeds of cultivated crops (Amaranth Information 1989). Indeed A. retroflexus is one of the most noxious and popular weeds of cultivated crops. Some breeding programs have been directed towards extracting and cloning amaranth genes that are resistant to herbicides like atrazines so that they could be transformed to common crops such as wheat, rice, corn etc. Weeding on amaranth plantations is usually manual and as a result of this cultivation suffers a setback.

1.9.2 Chenopodium quinoa aspect of study

Field preparation and sowing

In the development of quinoa as an arable break crop, sowing date, sowing rate and row spacing are identified as agronomic variables having a high priority for investigation. The variety Baer, from high latitudes at sea-level in Chile, and the variety Blanca de Junin, from the inter-Andean valleys of Peru, were sown on the 25th March, 14th April and 7th May 1982 at spacings between rows of 0.8 and 0.4 m and sowing rates within rows of 0.2, 0.4 and 0.6 g /m, at Cambridge, England. These varieties are chosen for their strong contrasting origins and plant types. In another experiment sown on 15 March 1984, Blanca de Junin was replaced by another valley type, Amarilla de Marangani, somewhat better adapted for cultivation in England. Between-row spacings of 0.4 and 0.2 m, and sowing rates of 15, 20 and 30 kg seed / ha were used. Weed competition was more intense after later sowings, causing the plots sown in May to be abandoned. At the higher sowing rates, plants were shorter, a higher proportion were stunted, branching was reduced and maturity was earlier. These effects were more marked in the valley varieties, particularly Blanca de Junin. Increases in within-row density caused greater increases in competition effects than corresponding reductions in row width, except for the effect on the proportion of branched plants. The highest grain yield, 6.96 t / ha, was obtained with Baer sown in March in rows 0.2 m apart at 20 kg seed / ha. However, Amarilla de Marangani produced a higher yield at 30 kg seed / ha than at 20 kg seed / ha, which is surprising since valley varieties are normally sown with low target population densities or in intercrop, and Amarilla de Marangani was, in other respects, less tolerant to competition than Baer.

Seed rates vary between United States recommendations and those of South America. Current United States recommendations are 8 million / ha for row cropping and 20 million / ha for broadcast cultural practices. Quinoa should be sown in a row distance of 24-26 cm in the middle of May (Danish conditions). The plant density should be 130-150 plants / m2. The recommended sowing depth is 1-2cm. In general the sowing period is between the beginning of April to May 31st (Haaber 1987).

Fertilizer requirement

Carmen (1984) postulated that the main agronomic advantages of quinoa are its ability to grow at high elevations under semi-arid conditions and marginal soils. Haaber (1987) stated that quinoa prefers sandy soils, and can be grown on clay soils but a reduction in green yield and subsequently dry matter may be expected as a consequence. He continued that in general the crop has adaptability for establishment and that compact, acidic and indigent nutritive conditions are unfavourable for proper crop propagation. Haaber (1987) also stated that a basal dressing of phosphorous and potassium equivalent to 65 kg P2O5 / ha and 65 kg K2O / ha respectively is recommended with 60 kg N / ha as a basic nitrogen fertilizer. He also recommended the use of 120-180 kg N / ha four weeks after emergence. Ritter (1985) has stated that quinoa is a plant with a high demand for nitrogen compared to other plants. He cited the German experience where a fertilizer application of 250 kg K2O / ha and 150 kg P2O5 / ha resulted in 170 dt / ha of DM and 700 dt / ha fresh weight.

Water requirement

Irrigation may have a significant effect on the yield of quinoa. Tapia (1984) indicated an average of 550 mm of available moisture as optimum. In the loamy soils typical of the valley quinoa types, 700 mm may be required while types which grow in the saltflats of Southern Bolivia require only 350 mm. In Colorado, Flynn (1990) found maximum yields of 1439 kg / ha were obtained on sandy-loam soils with 208 mm of water (rainfall and irrigation) with available water levels of 128, 208, 307 and 375 mm being tested. Haaber (1987) stated that warm weather, sunshine and suitable moisture in soil produce the optimum dry matter yield. Heavy drought and cold severly affect the yield.

Pests and diseases

Insects are a major concern in South America and have received increasing attention in the United States. In South America, Romero (1980) has pointed out two important pests of quinoa: Scrobipalpula sp. which destroys buds, inflorescence, immature and mature grain; and "leaf miner" (Liriomyza sp.) which destroys leaves and occasionally stacks of quinoa. In Colorado, Cranshaw et al (1990) found on quinoa some insects commonly associated with sugar beet and lambsquaters (C. album L). Seedling damage was caused by Malanotrichus coagulatus Ulher and Atomoscelis modestus Van Duzee and the seed bug, Nysius raphanus Howard. Foliar pests involve two leaf miners, Pegomyia hyoscyami Panzer and Monoxia nr. Pallida Blake. Also found were leaf feeding insects such as leaf curling aphid Hayhursita atriplitis (L.) and various Lepidoptera, such as Spodoptera exiqua Hubner. A foot, or root feeding aphid, Pemphgus populivenae Fitch, caused late season damage. Seed damage was due to Lygus spp.

Haaber (1987) stated that green and black flies Myzus persicae and Aphis fabae respectively have been identified as pest. Dawney mildew (Peronospora farinosa) has not been implicated as a disease attacking quinoa meant for vegetable use.

Quinoa as a weed

Weed control has a major impact on quinoa yield. It is largely manual for now, as in the subsistence agricultural systems of the Andes. This is so because a form C. album known in Britain as fat hen and lamb’s quarters in North America is distributed world-wide as an annual weed on arable land. The dividing line between a weed and a crop is often thin: the seeds of C. album were used as food by the former inhabitants of Russia, Denmark, Greece and northern Italy (Renfrew 1973). However where mechanization or chemical control is envisaged row width should be enlarged. In Colorado, grassy weed control alone increased yields from 640 kg / ha to 1822 kg / ha (Johnson 1990). In England, Metamazide, Propachlor, Linuron, Propyzamide and aloxium sodium did not significantly reduce plant stands of two quinoa cultivars (Galwey and Risi 1984). In Colorado preliminary herbicide studies of pre-emergent herbicides with Dual, Furloe, Sutan and Antor showed good crop safety and control of grasses and many broad-leaf weeds (Westra 1988).

Harvest

Harvesting for forage should be done nine weeks after emergence. When the dry matter and protein content are at maximum (Haaber 1987). Where the crop is meant for grain purposes, the optimum time for harvest is the stage of complete maturity of grains. In the Andes where the crop originates mechanical harvesting was unknown. However, in many temperate or mechanical environments where the crop is gaining increasing ground, mechanical harvesting is very much preferred. Growth attributes like reduction in plant height and early maturity did not play any role in the cultivation of quinoa as a subsistence crop. Presently screening and breeding research programs frequently include these attributes as they are proving increasingly essential if quinoa is to enter into urban and international markets (Risi and Galwey 1991). Carmen (1984) also stated the possibility of mechanical harvesting of plants.

Yield

To obtain high yields of a good quality animal feed from quinoa, the crop should be harvested nine weeks after emergence under northern conditions. Protein content and dry matter yield (DMY) would then be as follows: In the case of 180 kg N ha-1 fertilizer application, DMY is 11.4 t /ha while protein is 16.2%. If fertilizer application is 240 kg N ha-1 DMY is 10.7 t/ha and protein is 18.3% (Harber 1987). Indeed the response to nitrogen fertilization has been observed in both South America and Colorado (Gandarillas 1982).

With regards to grain yield, Weber (1978) stated that it varies according to growing conditions - from as low as 450 kg / ha to as high as 2000. The average yield is about 800 to 1000 kg/ha on the Altiplano. A record yield of about 5000 kg/ha has been reported under ideal conditions near Lake Titicaca, using cultivar Sajama developed in Bolivia.

Crop rotation

Weber (1978) stated that highland farmers often cultivate quinoa in rotation with other crops because they believe it can prevent diseases among other crops. Quinoa itself is a prey principally to mildew and leaf spot, though its most serious enemies are birds. According to an experiment in Equador (unpublished), it is risky to grow quinoa continuosly. The risk is the formation of two nematodes and one of them can attack potatoe (Solanum tuberosum). Therefore a good rotation is necessary as a precaution.

On the other hand, Risi and Galwey (1984) stated that one of the varieties investigated for use as a break crop namely Amarilla de Marangani, produced a higher yield at 30 kg seed / ha than at 20 kg seed / ha, which is rather surprising since valley varieties are normally sown with low target population densities or in intercrop. Although the implications of this result have got to be carefully analysed before conclusion, it can however be intuitively stated that there is proof of adaptability of the variety to temperate climate. Also it can be stated that there is a basis for further research as to its adaptability as a brake crop like rape. Indeed the results of the Cambridge experience suggested that C. quinoa is a good contender as a break crop like rape.

2 METHODOLOGY

2.1 GROWTH CONDITIONS

2.1.1 POT EXPERIMENTS

These experiments were set up with a view of investigating differences in gaseous exchange and harvest index (HI) due to fluctuations in the water table. Furthermore they were also meant to reveal actual differences in growth and yield between species and combinations. Plot experiments show water tables with diurnal, seasonal and climatic changes. The investigator has very little or nothing to do with regards to influencing the water table by way of water table fluctuations. The non-irrigated combinations in the two years field experiments (1992 and 1993), in particular, were independent of the investigator. On the other hand, the water table in the pot experiments was investigator descretional. The experiments were conducted with pots filled with 11.46 kg of a mixture of soil and sand 2:1 V/V. The soil moisture in the pot experiments had two levels. At high soil moisture level, 7.6% of the weight of the soil was moisture, 80% of the total pore space was filled with the moisture while the lower case had 5.6% of the weight of the soil, as moisture and 40% of the total pore space was filled with moisture. The moisture levels of 80% and 40% corresponds with soil moisture levels at field capacity and temporary wilting point respectively.

Fertilizer application was carried out on these pot experiments. Specific description concerning its application is explained under each experiment.

1992 INFRA RED GAS ANALYZER EXPT. (INFRALIT IV).

Two species Amaranthus cruentus and Chenopodium quinoa a Danish select were grown in pots prepared as mentioned above. The plants were transplanted into test tubes at the seedling stage. The roots were completely dipped in water. The plants were left in this state overnight to allow for a new equilibrium in its general metabolism in the new environment be fixed before measurements were started.

1992 EXPERIMENT

The seeds for this experiment were sown on the 14-02-92 and a lapse of 31 days was allowed for the plants to establish before they were transplanted into pots. There were 28 pots in all. Fourteen pots were assigned to each of the two species to cover two moisture levels. Each level had 7 pots. One level had soil moisture at field capacity (80%), while the other was at temporary wilting point (40%).

Field capacity is the water level of a soil system when all gravitational water has drained (Brady 1984). The percentage of the water in the soil was 7.6 that of the dry weight of the soil. The dry weight of the soil was 6 kg. The weight of the water in the pores was therefore 0.46 kg. The total weight was the sum of the weights of the dry soil, the water in the soil pores, the sand and stones plus the empty pot. If as earlier-mentioned the dry soil weighed 6 kg, the water in the pores weighed 0.46 kg the sand, stones and the empty pot together weighed 5 kg. The total weight was therefore 11.46 kg. The pF of soil was 2.4 which approximated 250 hPa.

The second level of soil moisture was intended to subject the plants to temporary wilting. This level of soil moisture was kept constant throughout the experiment as in the field capacity combination. At temporary wilting point the water level in the soil pores was 5.6% of the weight of the soil in the pot. The water weighed 0.3 kg of water when 100% of soil weighed 6 kg. The total weight of the pot 11.3 kg was the sum of the dry weight of the soil, the water in the soil pores, the sand, stones and empty pot. The pF was 3.0 and this was appoximately 1000 hPa.

Fertilizer application, (table 13), was carried out on both species. In the case of A. cruentus, there were three applications while there were two with respect to C. quinoa. The first application before sowing was similar in both species, while the second differ in composition with respect to species. There was a third fertilizer application for A. cruentus.

Two types of fertilizers were applied to each pot. There were those containing macroelements and those containing microelements. However in some applications there were no compounds containing microelements.

Combinations were differentiated out during the three leaf stage. Before then the plants in the pots were receiving the same treatment by way of addition of water.

1994 EXPERIMENT

The date of sowing was 20-05-94 and that of emergence was 22-05-94. The seedlings were transplanted on the 03-06-94. Combinations were separated out on the 05-06-94. The one day experiment was carried out during the flowering stage of growth on the 20th July 1994.

This pot experiment had similar fertilizer application, soil structure and composition as already mentioned for the 1992 experiment. The only difference in fertilizer application was that A. cruentus had no third application. The second fertilizer application took place on 08-07-94. Also the combinations which were based on soil moisture level were different. The experiment had two combinations for each species. Each combination had three pots. One of the combinations had constant moisture. The said moisture level was 7.6% the weight of the soil in the pot (80% of the pores were filled with moisture). The weight of the pot was maintained at 11.46 kg throughout the experiment. The other combination had an initial soil moisture level and weight of pot as the earlier-mentioned combination but no further addition of water was effected throughout the experiment.

2.1.2 PLOT EXPERIMENTS

The two years plot experiment involved in the growth analysis were set up against the same background, by way of species and combinations. There were two species, namely A. cruentus and C. quinoa a Danish select. There were two levels of soil moisture for each of the species. There was the combination that was exclusively rain-fed while the other level involved additional periodic irrigation, of about 4 mm per day excluding rainy days, with a view of preventing the harzards of temporary wilting. The species, quinoa, was Peruvian by origin from which a breeding line KLV 0188 was developed. The line is noted for, among others, beneficial characteristics for agronomic and mechanical propagation. The short vegetative period, the large contribution of the assimilatory surface area, lots of seeds, and the high protein content reaching 21% were among the noted characteristics. Each of the two species, in turn, had two combinations. One of the combinations was exclusively rain-fed while the other was irrigated from time to time, with a view of preventing the hazards of temporary wilting.

The experimental plots for the two years plot experiments were located on the site assigned to the Department of Plant Physiology of the Warsaw Agricultural University in Rakowiecka street. The crops were planted on a soil that comes under IIIB-IVA Bonification classes. Soil analysis done in the Department of Physiochemical Analysis of SGGW, in 1992 before sowing showed that N, P, Mg, Ca, K, Fe, Zn, Mn and Cu, had 1000, 860, 1380, 1825, 2650, 1069, 107, 116 and 12.9. Before the initial experiment in 1992 white mustard was growing on the plot as a break crop. The break crop was ploughed-in in winter. In spring the plot was aerated by harrowing.

Fertilizer was applied to all combinations. In the case of A. cruentus 100 kg/ha of nitrogen (urea) was applied. Initially 1/2 was applied before sowing, while the other 1/2 was applied during the stage of stem elongation. An application of 70 kg/ha of P in the form of Tri-superphosphate and 70 kg/ha of K (potassium salt) 60% was made before sowing.

In the case of quinoa 150 kg/ha nitrogen (urea) was applied. Two thirds was applied before sowing, while 1/3 was applied during the stem elongation stage. An application of 150 kg/ha of phosphorus P (Tri-superphosphate) and 150 kg/ha of potassium K (potassium salt) was made before sowing.

Each combination of the two species had four replications. The replications were carefully arranged so as to remove soil property differencies. The seed beds were 4 x 1.5m in dimension. Weeding on the seedbeds was manually done while harrowing between rows effectively suppressed weeds. In late June the crops were sprayed with Decis, against aphids.

Sowing was done in rows on the 18th of May in the case of A. cruentus in both cropping seasons. These dates correspond to the time when the spring chilling effect had passed away under Polish climatic conditions. The distance between rows was 30cm. The rows were laid across the breath of the shallow seed beds. Depth of sowing was 1cm. The seeds emerged a few days after sowing. In the case of the 1993 experiment a day or two was enough for the emergence, while four days were observed in 1992 for C. quinoa seeds. Moisture difference between the two years was considerable as there was more precipitation in 1993.

In the experiment of 1992 first thinning was done on the 02-06 -92, with respect to C. quinoa, (17 DAE). The second thinning on this same crop was done on the 09-07-92 (34 DAE). The first thinning on A. cruentus was done on the 14-06-92 (21 DAE), while the date for the second thinning coincided with that of C. quinoa on the 09-07-92, (47 DAE).

With regards to the experiment in 1993, the first thinning on C. quinoa was done on the 04-06-93, that is (14 DAE). The thinning on A. cruentus was done on the12-06-93, that is 22 DAE on the 21- 05-93. The second thinning in both crops was done on the 19-06-93, (29 DAE).

In 1992, there were eight aimed destructive harvests for A. cruentus done 28, 38, 49, 59, 70 79, 91, 99 DAE. With regards to C. quinoa there were seven such harvests carried out 38, 52, 61, 69, 81, 89, 102 days after emergence.

In 1993, there were ten aimed destructive harvests for A. cruentus carried out 22, 32, 42, 52, 62, 72, 82, 92, 102, 112 DAE while there were nine such harvests in the case of C. quinoa carried out 22, 32, 42, 52, 62, 72, 82, 92, 102 DAE.

2.1.3 METEOROLOGICAL PARAMETERS.

The total rainfall and daily mean temperature in 1992 are displayed as figure 38 while those of 1993 are displayed as figure 39 and the calculated Sielianinow’s hydrothermal index (1930) for the two consecutive years is displayed as figures 40.

K = [pic]

Where P - Total precipitation (in mm)

Where K - is the index of dryness

t - is the mean monthly air temperature in 0 C

When K is below 1, the climatic condition is described as dry. This condition will lead to plants losing more water through transpiration than it is receiving from precipitation. When K is below 0.5 the condition is described as intensive dryness.

2.2 GAS EXCHANGE MEASUREMENTS

2.2.1 POT EXPERIMENTS

1992 INFRA RED GAS ANALYZER EXPT. (INFRALYT IV).

PHOTOSYNTHESIS AND RESPIRATION

All the measurements of gaseous exchange were done using the Infra Red Gas Analyzer Infralyt IV, Jankalor, Germany. Three measurements involving three plants were carried out. The system included a cooler to facilitate chilling temperatures. The measurements were taken between 9 am and 1 pm . Avoidance of carrying out the measurements after 1 pm was deliberate as in winter, when the experiment was carried out, photosynthesis was observed to be tremendously reduced after 1 pm notwithstanding added artificial irradiance or other optimum conditions.

Seven temperature levels 10, 15, 20, 25, 30, 35 and 40 degrees centigrade were arbitrarily chosen for the taking of measurements. The temperature levels were meant to simulate Polish conditions. The assimilatory surface area was measured with the use of the Li-1000 planimeter equipment manufactured by Lambda instrument Corporation of Nebraska, USA. The time taken by the assimilatory surface of enclosed seedlings in the air-tight gas cylinder to reduce the CO2 concentration from 350 to 250 ppm was noted by a stop watch. The time, in seconds, was then slotted into equations to calculate the rate of photosynthesis. Dry matter of the samples was secured by oven drying at 1050 C for 1/2 h and then for 24 h at 750C.

Relative photosynthesis and relative respiration were deduced by dividing a given value by the highest one within the data at a particular temperature and the quotient expressed as a percentage. True photosynthesis expressed in mg of CO2 dm-2 h-1 (1 mg of CO2 dm-2 h-1 = 0.6313 ( mol-1 CO2 m-2 s-1) was the sum of photosynthesis and respiration at a given temperature. The ratio of photosynthesis to respiration (P/R) was the ensuing quotient when photosynthesis was divided by respiration.

In a bid to provide satisfactory irradiance two mercury lamps were used. One on each side of the chamber. Each lamp had a wattage of 250 and provided an average irradiance of 500 (mol m-2 s-2 inside the chamber.

The time taken for the concentration of CO2 in the Infra Red Gas Analyzer system, containing a sample of plant, to rise from 250-350 ppm was equally noted for the various temperatures (10-400 C). The time was then slotted again into the same series of deductions mentioned above, under photosynthesis, in obtaining the time in hours it takes for a given assimilatory surface area in dm2 of plant material to respire the given mass in mg of CO2. The glass cylinder itself was covered with a dark piece of cloth to allienate irradiance and hence promote respiration.

1992 EXPERIMENT

Gas exchange measurements were started a few days after combinations had been separated. The measurements were spread throughout until maturity of plants.

Below is the time schedule of some of the measurements.

04 - 03 - 92

06 - 03 - 92

15 - 04 - 92

02 - 05 - 92

12 - 05 - 92

The data were analysed with the use of Analysis of Variance (ANOVA) to test actual differences due to species and combinations in gas exchange, its parameters and other attributes. Furthermore regression analysis was carried out to test the strength of the relationship between gas exchange parameters. The pot experiments were harvested on the 29-05-92.

1994 EXPERIMENT

The first weight of pot when respiration rather than photosynthesis was recorded was the main objective of the combination. Gas exchange measurements were started at 11 30 am and were carried out every thirty minutes. The measurements were stopped at 1: 30 pm.

The data were analysed with Analysis of variance (ANOVA) to find the significant differences between species and combinations in gas exchange and other parameters. Among them were the internal concentration of CO2 (Ci ) and stomatal conductance (Cs).

2.2.2 PLOT EXPERIMENTS (1992 and 1993)

There were two plot experiments one in 1992 and another in 1993. These experiments involved periodic destructive harvests of the two species A. cruentus and C. quinoa a Danish select. A day before or after every aimed destructive harvest gas exchange measurements were made. The experiment lasted throughout the cropping season. Gas exchange parameters were measured using Li-Cor 6200 infra red gas analyzer.

In 1992 gas exchange measurements were carried out on the following dates:

12 - 07 - 92 23 - 08 - 92

24 - 07 - 92 30 - 08 - 92

03 - 08 - 92

14 - 08 - 92

In the following year (1993) gas exchange measurements were carried out on the following dates:

01 - 07 - 93 06 - 08 - 93

11 - 07 - 93 12 - 08 - 93

22 - 07 - 93

2.3 MINERAL RELATIONS

With regards to the mineral aspect samples were drawn from two destructive harvests. One of them was at maximum leaf area index (LAI) while the other was at the end harvest. Coincidentally there were instances when the maximum LAI occured in the end harvest.

Macro and micronutrient analysis was carried out on the branches, leaves, seeds and stems. The organs were first grounded. Two grams of sample in two replications was heated in the oven to a temperature of 4500C for three days. The ash was dissolved in a 20% 5ml of Hcl. The solution was later transfered to a 25ml volume flask and then the contents were made up to the level of the meniscus with redistilled water. The contents were diluted ten or hundred times before determination, depending on the element. Determination of Ca, P, Mg, K, Na, Fe, Zn, Cu, and Mn was made by the Atomic Absorption Photospectrometer (AAS) instrument. Nitrogen was determined by the kjeldahl method and 0.5g of subsample was used for the determination. The reading from the instrument was then multiplied by the factor 6.25 to calculate crude protein (%CP).

The means were then compared for differences due to species, combinations and cropping season.

2.4 PHOTOASSIMILATE DISTRIBUTION EXPERIMENT (1993)

The pot experiment was set up with a view of testing eventual differences between both studied species and combinations, in the partitioning of photoassimilates. There were two combinations for each species just as already described under section 2.1.1. The fertilization of the plants was also similar to that already stated under the afore-mentioned section.

Labelling of the plants with 14CO2 was done during the early flowering stage. The whole pot was placed in a temperature controlled chamber connected with IRGA in a closed system. The chamber was illuminated by placement under direct sunshine to provide satisfactory irradiance. After the steady state was achieved (on the basis of time needed for 100 umol m-2 s-1 of CO2 absorption in the range 350-250 (mol mol-1 ) the plants were exposed to 4 ( Ci of 14CO2 which had been injected by a syringe into the system. Radioactive CO2 was generated by addition of sulphuric acid to labelled sodium bicarbonate in the following reaction:

NaH 14CO3 14CO2

+ H2SO4 ( Na2 SO4 + + 2H2O

NaH 12CO3 12CO2

The remaining 14CO2 was fixed by KOH.

Immediately after exposure the first harvest was done. The second harvest was done two weeks after labelling. The harvested plants were randomly sampled from pots. There were three pots for both soil moisture combinations in each species making a total of 12 pots in the experiment. Three plants were drawn from each combination at each harvest. This amounted to a total of twelve plants for each harvest.

Each harvested plant was separated as leaves which were divided into top, mid and bottom, the inflorescence, stems, petioles, branches and fallen leaves. Dry weights of specific organs were recorded and then the plant material was grounded into a fine powder. Two subsamples weighing between 0.5-1.0g, were taken for oxidizing in the Packard sample oxidizer 300. Radioactivity was measured by the Beckman liquid scintilation counter LS 8000.

The counts per minute (cpm) from the Beckman were first transformed into disintegrations per minute (dpm) by interpolating from a standard curve. The standard curve had efficiencies on the Y-axis while the H# or sample channel ratios (SCR) occupied the X-axis. The H# and the SCR were automatically supplied by the program in the LSC developed for counting the radioactivity.

The curve was drawn by calculating the efficiencies of quenched and unquenched factory radioactive samples in factory-sealed vials. The calculation required observed values (cpm) and expected values (dpm). The expected values were supplied by the manufacturers.

The radioactivity of each organ was derived by establishing a relationship between the radioactivity of the subsample and the weights of the subsample and that of the organ itself. The specific radioactivity was derived by dividing the radioactivity of organ or subsample by the weight of organ or subsample. The total radioactivity was the sum of the radioactivities of the contributing organs.

2.5 GROWTH ANALYSIS (1992 and 1993)

The classical methods of growth analysis were used to follow the growth and dry matter (DM) accumulation of the two species in their two combinations during the cropping seasons involved (1992 and 1993).

INDICES OF GROWTH

Periodic aimed destructive harvests were carried out. Each time five plants were harvested from each replication. Forty plants were harvested from each combination. An equal number of forty plants were also havested from each species at each destructive harvest. This made a total of eighty plants at each aimed destructive harvest. The aerial parts of the plant were involved in the analysis. Therefore the plants were cut at the base of the stem. The roots were excluded. Ideally, all living tissue of the crops growing in the sampled area should be measured, but the difficulty of sampling roots often excludes their use in some crop growth rate (CGR) studies.

The plants were later separated into Leaves, stems, branches, petioles, inflorescence and seeds. For one plant of each combination of every species total assimilatory surface area was measured separately. The measurements were made with the use of photoplanimeter 3000A, (Lambda Instruments Corporation, Nebraska, USA). The surface area of the stem was calculated as 1/3 the product of the circumference and the length. The total surface area of each organ of the five plants in each combination was calculated by establishing a relationship with the earlier-measured single plant surface area. The dry matter (DM) of each organ was determined separately and then that of the whole plant was calculated as the cumulative DM of the organs.

Other indices like Crop Growth Rate (CGR) and Leaf Area Index (LAI) were calculated using the basic attributes such as assimilatory surface area, ground surface area covered by the assimilatory surface area and sometimes a combination of the said attributes and other indices calculated by the IBM program earlier-mentioned.

The indices used in the growth analysis were divided into two groups. One of the groups consists of indices dealing with single plants while the other group consists of indices dealing with canopies.

SINGLE PLANTS

1) RGR (Relative Growth Rate). This is the change in biomass (dW) per unit of

existing biomass.

[pic] = [pic]=[pic]

2) ULR (Unit Leaf Rate). The index is otherwise called NAR (net assimilation rate). It is the change in biomass (dW) per unit time (dt) not less than a 24-hour day, per unit of any measurable attribute of the assimilatory surface (assimilatory surface area, chlorophyll etc.).

[pic] = [pic]= [pic] This equation is employed on the assumption

that alpha assumes values from 1.5-2.5.

3) LWR (Leaf Weight Ratio). This is the contribution of the assimilatory surface area (WL) in the total dry matter (W).

LWR = [pic] Where W is the biomass of the whole plant.

[pic] = [pic]/LWR1 + LWR2/ Where the LWR1 and LWR2 are the values of two successive measurements.

4) SLA (Specific Leaf Area). The index relates the area of the assimilatory surface area (A) to its biomass (WL ).

SLA ( [pic] Where WL is the biomass of the leaves.

[pic] = [pic]/ SLA1 + SLA2/ Where SLA1 and SLA2 are the values of the index for successive harvests.

5) LAR (Leaf Area Ratio). The index relates the assimilatory surface area (A) to the biomass of whole plant (W).

LAR = SLA + LWR = [pic] + [pic] After cancellation of common terms

LAR becomes:

LAR = [pic]

[pic] = [pic]/LAR1 + LAR2/ Where LAR1 and LAR2 are the values of

the index for successive harvests.

Relative Growth Rate (RGR, R), Unit Leaf Rate, (ULR) Leaf Area Ratio (LAR), Leaf Weight Ratio (LWR), Specific Leaf Area (SLA), used in following the growth and development of single plants and clones were calculated using computer program “Jantar” developed by Tarlowski (1992).

canopy

1) CGR (Crop Growth Rate). The change in the canopy biomass (dWc) per unit time not less than a 24-hour day, per unit ground surface area covered by crop (P).

[pic] = [pic] x [pic] = [pic] x [pic] Where Wc1 and Wc2 are the

values of the attribute for successive harvests.

2) LAI (Leaf Area Index). This is the ratio of the assimilatory surface area of a canopy to the surface area of the ground (P) covered by that canopy.

LAI = [pic]

[pic] = [pic]/LAI1 + LAI2/ Where LAI1 and LAI2 are the values of the 2 index for successive harvests.

3) ULRc (Unit Leaf Rate). This is the specific productivity (Net Assimilatory Rate) of a canopy. It is the change in biomass of a canopy (dWc) per unit time, not less than a day, per unit of the surface area of all the assimilatory organs in the canopy (Ac) (Pietkiewicz 1985; 1985a).

[pic] = [pic] x [pic]

4) LAD (Leaf Area Duration). This is the index that denotes the time the crop had assimilatory surface. Which very often seems to be more important than LAI. It is

calculated as the summation of the LAI over the period the crop has been carrying the assimilatory surface.

Indices like Crop Growth Rate (CGR) and Leaf Area Index (LAI) were calculated using the basic attributes such as assimilatory surface area, ground surface area covered by the assimilatory surface area and sometimes a combination of the said attributes and other indices calculated by the IBM program earlier-mentioned.

STATISTICAL CALCULATIONS

Statistical operations were employed on the measurable attributes such as mass and area of plant material. There were measures of central tendency such as the arithmetic mean. To find the significant differences ANOVA method as well as variance and standard deviation were employed too.

3 RESULTS

3.1 GAS EXCHANGE EXPERIMENTS

3.1.1 INFRA RED GAS ANALYZER EXPERIMENT, INFRALYT 4

In (fig. 1 (I)) quinoa had the higher photosynthetic value at 10o C and the same result was also observed at 15o C and 20oC when quinoa had its maximum photosynthesis. It was also observed that the gradient of amaranth was all the time rising steadily.

The photosynthesis of quinoa dropped steeply after the 20o C maximum, while that of amaranth was rising. The photosynthesis rate of amaranth reached its maximum level at 35o C after that it started to fall with a steep gradient. The recorded fall at 40o C of amaranth initial while it was the least for quinoa.

The respiration of quinoa (fig. 1 (II)) was higher at 10o C than that of amaranth. It rose with a steady gradient reaching a peak at 25o C, before it started falling. The respiration of amaranth on the other hand rose from 10o C to 20o C with a somewhat small gradient. Above 20o C that it started to rise steeply until 30o C. After that it started to rise with a small gradient. A fall in respiration was not recorded for amaranth. The fall in respiration of quinoa between 25o C and 40o C was with a small gradient relative to the rise observed between 10o C and 25o C.

In (fig. 2 (I)) the ratio of photosynthesis to respiration is clearly higher for amaranth than quinoa at the initial temperature of 10o C. The ratio increased through 15o C to 20o C which was the climax. It fell steeply at 25o C and continued falling till 35o C with a small gradient. It again fell steeply at 40o C. The ratio of quinoa rose steeply from 10o C to 25o C. It then levelled off between 25o C and 30o C, before it started falling through 35o C to 40o C with a small gradient relative to the one it rose. The ratio of photosynthesis of quinoa had lower values than that of amaranth throughout. In (fig.2 (II)) the true photosynthesis of quinoa was initially higher than that of amaranth. The curve rose steeply to a maximum at 20o C, before it started falling. It fell right through to 40o C. The true photosynthesis of amaranth rose steadily until 35o C. Then it fell to 40o C with a steep gradient. It was observed that the true photosynthesis of quinoa was higher than that of amaranth up to 25o C. It was after that temperature an inversion of that progression was observed.

The relative photosynthesis and relative respiration for both amaranth and quinoa are shown on (fig. 3).

3.1.2 POT EXPERIMENT (1992)

The means of photosynthesis ranged 9.46-30.35 and 8.5-23.7, 4.47-6.68 and 5.38-9.05 (mol m-2 s-1 for A. cruentus in the low and high soil moisture levels and for C. quinoa a Danish select in the low and high soil moisture combinations respectively. The original data are not shown here. The internal concentration of CO2 varied from 49.26-245.67 and 31.4-233.07, 141.73-179.2 and 155.70-232.8 (mol mol-1 in the same combinational order as in photosynthesis. Transpiration ranged from 1.2-9.3 and 1.1-5.9, 0.77-1.23 and 1.13-3.4 mmol H2O m-2 S-1, in the same respective order as in photosynthesis. Irradiance ranged from 420.57-1218.33 and 194.9-1249.3, 227.17-303.4 and 206.07-797.87 (mol m-2 s-1 in the same order as in photosynthesis. The stomatal conductance (Cs) was 0.15-0.91 and 0.12-0.89, 0.09-0.16 and 0.13-0.92 cm s-1. The water use efficiency ranged from 3.55-9.0 and 3.00-9.82, 5.00-6.00 and 5.00-8.00 (mol CO2 mmol H2 O-1 in the same order assigned to photosynthesis.

The effect of soil moisture on the DM of the plant organs of this experiment are displayed as (fig. 4) while that on the length and DM of the whole plant are displayed as (fig. 5A and 5B) respectively. The denotation DM in figure 4 means dry matter while HSM and LSM in the legends of (fig. 4 and 5) mean high and low soil moisture combinations respectively.

The effect of soil moisture on the DM of organs (fig. 4) showed that high soil moisture combination of amaranth had the heavier weight almost 4.5g of leaves while the low soil moisture combination had about less than 4g. The leaves of the high soil moisture combination of quinoa were also heavier than those of the low soil moisture combination. The leaves of amaranth were heavier than those of quinoa.

The stems of the high soil moisture level of amaranth (fig. 4) were heavier than those of the low level combination. In quinoa the difference between the two combinations was greater. The high soil moisture combination had the higher value.

The seeds of the high soil moisture of amaranth had heavier seeds than the low soil moisture combination. In quinoa the difference was again observed to be greater and the higher case moisture level clearly led. The amaranth seed values were higher than those of quinoa. The higher moisture level of amaranth led in the weight of roots. The same was observed in the case of quinoa. The difference was also observed to be wider for quinoa between the two soil moisture levels. Between species revealed that quinoa had the higher value.

The high soil moisture level of amaranth (fig. 5 (A)) had the longer lengths of plants than the lower moisture case. The same was observed for quinoa although the difference was almost indiscernible. When the two species were compared quinoa had the longer lengths of plants.

At the whole plant level (fig. 5 (B)), the high moisture case of amaranth outweighed the lower moisture one. The same was observed in quinoa. Comparison between species showed that amaranth outweighed quinoa.

3.1.3 POT EXPERIMENT (1994)

Photosynthesis ranged from 27.1-32.4, 14.6-30.5, 11.2-29.52 and 1.21-29.3 umol m-2 s-1 for A. cruentus for the constant and variable soil moisture combinations and for C. quinoa constant and variable soil moisture combinations respectively. The internal CO2 concentration ranged from 64.5-83.7, 54-78, 161.5-202.13 and 160.1-198 (mol mol-1 in the same respective order as mentioned above for photosynthesis. Transpiration ranged from 3.4-5.1, 2.51-4.61, 4.2-8.8 and 1.0-8.7 mmol H2O m-2 s-1 in the same respective order as in photosynthesis. The stomatal conductance varied from 0.45-0.61, 0.21-0.54, 0.34-0.81 and 0.08-0.82 cm s-1 in the same respective order as in photosynthesis. The water use efficiency (WUE) varied from 5.4-9.6, 5.6-9.9, 1.8-3.3 and -1.1 to 3.4 umol CO2 mmol H2O-1 in the respective order assigned to photosynthesis.

The results of photosynthesis for the variable and constant moisture for A. cruentus and C. quinoa in 1994 are displayed as (fig. 6).

3.1.4 FIELD (PLOT) EXPERIMENT (1992)

Photosynthesis ranged from 23.86-57.98 and 18.77-43.35, 15.42-45.34 and 13.96-36.76 umol m-2 s-1 for A. cruentus irrigated and non-irrigated combinations, C. quinoa irrigated and non-irrigated combinations respectively. The internal concentration of CO2 ranged from 16.8-180.70 and 31.58-192.77, 161.4-225.43 and 145.23-279.4 (mol mol-1 in the same respective order as in photosynthesis. The transpiration ranged from 2.6-9.1 and 2.37-9.2, 4.2-13.7 and 3.6-11.3 mmol m-2 s-1 in the respective order mentioned above for photosynthesis. Irradiance varies from 884.3-1636 and 914.3-1466, 881.8-1469.67 and 529.47-1221 umol m-2s-1 in the same respective order above for photosynthesis. The stomatal conductance ranged from 0.56-1.99, 0.27-2.35, 0.49-2.39 and 0.38-2.48 cm s-1 in the same order as in photosynthesis. The water use efficiency (WUE) ranged from 4.2-15.4, 4.2-9.0, 2.1-7.5 and 2.2-4.9 umol CO2 per mmol H2O, in the order earlier-mentioned in photosynthesis.

3.1.5.FIELD EXPERIMENT (1993)

Photosynthesis ranged from 33.07-37.38 and 21.48-40.03, 25.05-46.35 and 15.51-44.04 umol m-2 s-1 for A. cruentus irrigated and non-irrigated combinations, C. quinoa irrigated and non-irrigated combinations respectively. The original data are not shown here. The internal CO2 concentration ranged 120.39-191.11, 101.21-180.6, 94.53-268.19 and 103.13-257.48 ppm in the same combinational order assigned to photosynthesis above. Transpiration ranged from 2.3-3.4 and 1.4-4.8, 2.2-15.2 and 2.3-9.7 mmol H2O m-2 s-1 in the respective order earlier-mentioned. Irradiance ranged from 1007.54-1752.66 and 1123.5-1535.89, 1176.25-1643.25 and 831.73-1659.22 umol m-2 s-1 in the respective order assigned to photosynthesis. The stomatal conductance ranged from 0.52-1.36 and 0.34-1.66, 0.49-3.75 and 0.54-2.69 cm s-1 in the respective combinational order assigned to photosynthesis. The water use efficiency (WUE) ranged from 9.7-16.3 and 6.1-9.5, 3.0-11.4 and 3.5-10.9 umol CO2 per mmol H2O in the respective order assigned to photosynthesis.

3.1.6 HISTOGRAMS

The influence of soil moisture on photosynthesis of amaranth and quinoa is presented as (fig.35). In (fig. 35 (I)), the irrigated amaranth had a mean of 35 umol m-2 s-1 in 1992. It was 35.3 umol m-2 s-1 in 1993 while the grand mean derived by taking the average of the two means was also 35.2 umol m-2 s-1. In the irrigated quinoa (fig.35 (I)), the observation was markedly different from that of amaranth. In 1992 the mean photosynthesis was about 27.6 umol m-2 s-1 while it was 32.6 in 1993 and the grand mean was 30.1.

In (fig. 35 (II)) the non-irrigated value of amaranth in 1992 was 28.4 umol m-2 s-1 while it was 30.9 in 1993 and the grand mean was 29.2 umol m-2 s-1. Quinoa had a value of 25.2 umol m-2 s-1 in 1992 while that in 1993 was 28.5 and the grand mean was 26.9 umol m-2 s-1 The influence of soil moisture, cropping season and species on the Water Use Effiency (WUE) was displayed as fig. 36. In (fig.36 (I)) the mean for amaranth in 1993 was higher than in 1992 The same was observed between cropping seasons for quinoa. The value of amaranth was higher than quinoa in both years. In (fig. 36 (II)) the same was observed between cropping seasons and species as in (fig. 36 (I)).

The influence of soil moisture treatment, cropping season and species on yield per plant are displayed as (fig.37). In (fig. 37 (I)) the yield per plant was higher in 1992 than in 1993 for amaranth while the the opposite was observed for quinoa. In 1992 the value of amaranth was higher than quinoa while that of quinoa was higher than amaranth in 1993.

In (fig.37 (II)) the amaranth value was higher in 1992 than in 1993, while in quinoa not much difference was observed between cropping seasons. In 1992 the value for amaranth was double that of quinoa. In 1993 amaranth was also higher in value but the difference was not much.

In (fig 35 (I)) the mean of amaranth was calculated from 32.52, 51.36,24.04, 22.41 and 34.65 umol m-2 s-1 taken on the 12th July, 24 July, 03 August, 14 August and 23 August 1992. The mean for quinoa was from the values 21.88, 44.79, 23.58, 24.39 and 19.91 umol m-2 s-1 also taken on dates corresponding to those of amaranth in 1992.

In (fig. 35 (I)), 1993, amaranth values were 32.52, 51.36, 24.04, 22. 41 and 34.65 taken on the 12 July, 24 July, 03 August, 14 August and 23 August. The mean for quinoa in (fig. 35 (I)) was calculated from the values 22.46, 44.79, 23.58, 23.11 and 15.67, taken on dates corresponding to those of amaranth in 1993.

In (fig. 35 (II)), 1992, the amaranth mean was derived from 22.27, 44.16,23.17, 18.76 and 29.63 taken on dates earlier-mentioned for the irrigated amaranth in (fig. 35 (I)). The mean for quinoa was from the values 17.96, 26.85, 18.78, 22.59 and 14.23 umol m-2 s-1 taken on dates earlier-mentioned for quinoa in 1992.

In (fig. 35 (II)), the amaranth mean in 1993 had original values of 22.27, 23.17, 18.76 and 29.53 while they were 17.95,26.84, 19.85, 60.81, 21.83 and 14.22 for quinoa during corresponding measurement dates already mentioned under (fig. 35 (I)).

A comparative histogram presentation between the two years field experiments, 1992 and 1993, are displayed for photosynthesis, water use efficiency and final yield as (fig. 35, 36 and 37) respectively. Analysis of variance of the three attributes between species, soil moisture and cropping seasons is presented as table 4.

3.2 PHOTOASSIMILATE DISTRIBUTION

During the first harvest analysis of variance (ANOVA) revealed significant differences in the total radioactivity between species in the top leaves and highly significant differences in the mid and bottom leaves, flowers and branches of the low soil moisture combination (fig. 6 and 7). Amaranth had higher value than quinoa in all the organs except the flowers and branches. The high soil moisture combination of the same harvest also revealed highly significant differences between species in the top, mid and bottom leaves while significant differences were found in the flowers and petioles. Amaranth had the higher value with respect to the top, mid and bottom leaves as well as the petioles, while quinoa had the higher value in the flowers. Non-significant differences were found between species in the stems.

Between soil moisture comparison within species in the first harvest revealed significant differences in the flowers, stems and petioles as well as the bottom leaves in amaranth. The high soil moisture combination had the higher values in all the organs except the bottom leaves. Highly significant differences were found in the top and bottom leaves as well as the branches in quinoa, while significant differences were found in the stems and petioles. The high soil moisture combination had the higher values in the branches, stems and bottom leaves while the low soil moisture combination had the higher value in the top leaves and the petioles. The remaining organs in quinoa revealed non-significant differences in this form of comparison.

During the second harvest significant differences were found between species in the top and middle leaves, while highly significant differences were found in the flowers, stems, petioles and branches of the low soil moisture combination. Except for the branches amaranth compared favourably to quinoa in the rest of the organs. In the high soil moisture combination, comparison between species of the second harvest revealed highly significant differences in the top, mid and bottom leaves as well as the branches. Amaranth compared favourably to quinoa in all the organs except in the branches. The flowers and the stems revealed non-significant differences. Between soil moisture combination in the second harvest revealed significant differences in all the organs of amaranth except the top leaves and the flowers. The high soil moisture level had the higher values in all the organs. In quinoa significant differences were found in the branches, petioles, fallen leaves, top and mid leaves while highly significant differences were found in the bottom leaves, flowers and stems. The high soil moisture compared favourably to the low soil moisture in the flowers, stems, branches and fallen leaves while the low soil moisture combination had the higher values in the remaining organs. The interaction of the species and soil moisture was found to be highly significant in the flowers.

The comparison based on harvest revealed significant differences in the top and bottom leaves, as well as flowers, while mid leaves were highly significant and stems were significant in the high soil moisture combination of amaranth. Non-significant differences were found in the petioles. In the cases investigated the second harvest had higher values in the flowers and the stems, while the first harvest had higher values in the rest of the organs. The top and bottom leaves, stems, petioles and branches revealed significant differences in the high soil moisture combination of quinoa while the mid leaves and flowers were found to be highly significant. The second harvest had the higher values in the top leaves, flowers and stems, while the first harvest had the higher values in the other organs.

In the low moisture combination between harvests comparison in amaranth revealed significant differences in the top, mid and bottom leaves as well as flowers and stems while branches showed high significance. In the top, mid and bottom leaves as well as the branches the first harvest had the higher values while the second harvest had the higher values in the flowers and stems. Non-significant differences were found in the petioles. In quinoa significant differences were recorded in the top, mid and bottom leaves, as well as the flowers, stems and petioles. The fallen leaves showed a high level of radioactivity while the branches revealed non-significant differences. In the bottom leaves and the stems the second harvest had the higher values while in the rest of the organs the first harvest had the higher values.

3.3 GROWTH ANALYSIS

ASSIMILATORY SURFACE INCREMENT AND BIOMASS

ACCUMULATION

The results of the basic attributes of assimilatory surface increment and biomass accumulation for 1992 and 1993 cropping seasons showed that leaf area development (fig. 7 and 8) preceded DM increase. The above-mentioned observation, of leaf area preceding biomass accumulation, holds in both species for the two years experiments. This was also the case throughout the stages of development. Chenopodium quinoa was more robust in growth. It was higher in value of attributes for both the treatments (combinations) and during both cropping seasons than A. cruentus. Between combinations within species revealed marked differencies in the value of attributes. The irrigated combination had higher values most of the time.

ASSIMILATORY SURFACE INCREMENT

In 1992 the ASI curves for both the irrigated and non-irrigated combinations of A. cruentus (fig. 7(I)) rose steeply between the harvests at 28 and 38 DAE. The differences between the two curves was very small. Between 38 and 49 DAE the curves were still rising but the irrigated had higher values. The period between 49 and 59 DAE also revealed rising ASI and the irrigated still had the higher values. The plants may have benefited from the improved moisture condition around the 10th of July about 49 DAE. The period between 59 days and 70 DAE revealed a steep rise in the index of the irrigated while that of the non-irrigated was nearly stable. The irrigated combination may have benefited from the irrigation while the non-irrigated might have been hit by the continued low moisture level. The period between 70 and 79 DAE however revealed a fall in both curves because of the continued low moisture. Between 79 and 91 DAE both indices rose probably due to the improved moisture. The irrigated reached its maximum 91 DAE. The period between 91 and 99 DAE therefore revealed a fall in the index of the irrigated. During the same period the non-irrigated benefited from the improved moisture condition to increase its assimilatory apparatus. This was shown by a steep rise in the index.

In 1992 the assimilatory surface curves of the irrigated and non-irrigated combinations of C. quinoa (fig. 7(II)) rose steeply between 38 and 52 DAE. The plants might have benefited from the optimum moisture condition around the 10th of July. Between 52 and 61 DAE the curve of the irrigated combination fell, while that of the non-irrigated was somewhat stable. This was probably due to the depreciating moisture condition. During the period between 61 and 69 DAE both curves fell steeply. This was also coincidental with depreciating moisture condition. The period between 69 and 81 DAE revealed a steep rise in the index of the irrigated while that of the non-irrigated fell. The fall was however markedly lower than the one recorded during the previous period. During the period between 69 and 81 DAE a rise was recorded in the Silianinow hydrothermal index (fig. 40). The improved moisture condition may have been reflected by the indices during that period. The curve of the irrigated having reached its maximum at the end of the previous period fell steeply, between 81 and 89 DAE. A fall was also recorded in the non-irrigated but the gradient was also lesser than that of the previous period. The situation might have reflected the improved soil moisture towards the end of the cropping season. The period between 89 and 102 DAE revealed a further steep fall in the index of the irrigated while that of the non-irrigated somewhat rose slightly.

In the beginning of 1993 the assimilatory apparatus in both the irrigated and non-irrigated combinations of A. cruentus (fig. 8(I)) increased between 22 and 42 DAE. The gradients of the curves were however small. The irrigated had the higher values. The period between 42 and 52 DAE revealed a steep rise in the indices of both combinations. The moisture was optimum all the time. The rise in the indices continued between 52 and 92 DAE days in the irrigated combination. The curve having reached its maximum 92 DAE, fell between 92 and 112 DAE, even though the moisture condition was optimum. The non-irrigated curve on the other hand was rising all the time even when the irrigated fell between 92 and 112 DAE. The non-irrigated might have benefited from the improved moisture conditions towards the end of the cropping season. The difference in the values of the indices between the irrigated and the non-irrigated was increasing rapidly. Between 62 and 92 days when the moisture conditions were sub-optimal, as indicated by the hydrothermal index, wider differences were revealed between the irrigated and non-irrigated combinations. During this period the irrigated was probably benefiting from the provided water to keep most of its leaves intact while the non-irrigated had to shed some of its assimilatory apparatus to minimize transpiration losses.

The irrigated and non-irrigated assimilatory surface increment curves of C. quinoa during the 1993 cropping season, were overlapping during the period between 22 and 32 DAE. The moisture was optimum by then and there was little difference between the irrigated and the non-irrigated. The next period between 32 and 42 DAE revealed a divergence of the curves with the irrigated having the higher value 42 DAE. After the local maximum the irrigated dropped suddenly to a local minimum 52 DAE. By then the non-irrigated rose. This may be due to the elevated moisture during this period. The non-irrigated which was frequently subjected to temporary wilting may have tremendously benefited from the elevated moisture while the irrigated, which had little or no low moisture effects, negatively reacted. The period between 52 and 62 DAE revealed a steep rise in the index of the irrigated. The moisture was falling by then. The level may have been optimum for the irrigated combination. At the same time the curve of the non-irrigated also rose. During the period between 62 and 92 DAE both curves were rising. The depreciating moisture during the period 72 and 82 DAE did not cause a fall in the curves of both combinations. This may have been due to the fact that the plants were able to use the large assimilatory apparatus earlier-acquired to add more to its assimilatory surface. Both curves fell steeply between 92 and 102 DAE .

DYNAMICS OF BIOMASS ACCUMULATION

The dynamics of biomass accumulation results are displayed as (fig. 9 and 10). In 1992, (fig. 9), the curves differ in both species and combinations. Amaranthus cruentus was sown two weeks before C. quinoa. The dynamics of biomass accumulation was however more pronounced in C. quinoa than in A. cruentus. The climatic conditions in 1992 after A. cruentus were sown on the 18th of May 1992 was such that several rainless days followed. It was not condusive for robustness in growth. Chenopodium quinoa was sown on the 2nd of June 1992. It had a good start with respect to moisture conditions. The hydrothermal index was greater than unity before sowing. The necessary conditions of optimum soil moisture for germination were assured.

The Amaranthus cruentus aspect of the dynamics observation showed that until 91 DAE, the two combinations were increasing all the time. The irrigated curve dropped down after 91 DAE and continued dropping right on to 99 DAE. On the other hand the non-irrigated curve continued to rise. During the 1992 cropping season the two combinations of C. quinoa were following a similar trend up to 59 DAE, the non-irrigated fell while the gradient of the irrigated curve which had started reducing in the previous period continued until 70 DAE. After that the two curves swiftly continued to rise until the 91DAE when ontogeny caught up with the irrigated combination. The non-irrigated combination on the other hand was rising all the time.

In 1993, (fig. 10), the course of A. cruentus dynamics curve was similar in both combinations, in that the curves were rising all the time. The same situation was observed in C. quinoa. In both crops, the non-irrigated combination had lower values throughout the cropping season though the difference was more marked in quinoa.

RGR

The relative growth rate curve (RGR), henceforth refering to whole plant, in A. cruentus (fig. 11(I)) initially fell. The situation could be attributed to the low precipitation that preceded the second harvest 38 DAE. Only once did the hydrothermal index was above unity. The curve rose with a somewhat minimal gradient from 49 DAE to 59 DAE. The situation might be due to two reasons. One reason might be the second fertilizer application about 58 DAE. The fertilizer application was accompanied by weeding and second thinning which led to aeration of the soil and improvement in the soil structure. It might also be due to the brief improvement in moisture condition before the 3rd harvest as manifested by the increased hydrothermal index. After 59 days after emergence the RGR curve fell again. Among other things the low moisture level as manifested by the hydrothermal index which was below 0.5 might have been a prominent reason. Equally important was the appearance of inflorescence during the 70 days after emergence. These generative organs are stronger acceptors of photoassimilates than branches. The branches also manifested a reduction in their contribution to RGR. A situation that made things worse as branches are supposed to be assurances against stressful situations. The stagnation of the curve, between 70 and 79 DAE respectively, may be due to the improved moisture condition as indicated by the hydrothermal index. The relative lack of importance of the contribution of branches to RGR was manifested between 70 and 79 DAE. Notwithstanding the reduction of the contribution of the branches, the RGR was steady. The index rose again after 79 DAE. The rise may be attributed to improved weather condition manifested by the hydrothermal index which rose and almost reached the 6th grade. The temperature also reduced after increasing around 94 DAE. The contribution of all the organs except the petioles to RGR was remarkable. After 91 DAE harvest ontogenetic drift caught up with the index.

The situation in the non-irrigated combination of A. cruentus (fig. 11(II)) was somewhat different. The idex fell down to 0.04 while in the irrigated combination it was above 0.1 a situation that reflected the stressing moisture condition as manifested by the hydrothermal index which for most of the time was less than unity before 49 DAE. It is not surprising that the intensity of the stress on RGR was such that the branches which are generally considered assurances against stressful conditions started appearing during this harvest, while branches did not appear in the irrigated combination until 59 days after emergence. It should be noted that the percentage contribution of the branches in A. cruentus, in general, is small unlike C. quinoa as shown in (fig. 12 and 14). The contribution of the branches to RGR slightly increased 79 days after emergence to almost 0.3. In the case of the irrigated combination the appearance and development of the generative organs during the period between 70 and 79 DAE coincided with leveling in RGR curve and also marked reduction of the contribution of the branches was observed. During this same period in the non-irrigated combination an increase in the index was the case. This increase coincided with an increase in the contribution of the branches notwithstanding the appearance and development of the generative organs. This fact may lend credence to the further fact that the contribution of the branches was very important in RGR for the non-irrigated combination. The irrigated combination was in a better position to avoid the hazards of temporary wilting while the non-irrigated combination was constantly subjected to it.

The index fell during 91 DAE. The appearance of the seeds and the reduction in the contribution of the inflorescence might have been implicated in the phenomenon. The branches on the other hand took advantage of the improved weather condition to add to its enormous biomass realized 79 DAE. The rainfall reached its maximum value of about 78mm around this harvest. The beneficial effects of the improved moisture condition 91 DAE were manifested 99 DAE. The contribution of the maturing seeds, the leaves and the stems to the increased RGR rather made trivial the reduction in the contribution of the branches, inflorescence, and petioles. This situation was very much opposite to the irrigated combination when the contribution of all the organs reduced and in turn resulted in the fall of the index.

The index for the irrigated combination of C. quinoa in 1992 fell 61DAE, (fig. 12(I)). The precipitation was low at the time of the harvest. It also coincided with the formation of inflorescence which are stronger acceptors. They developed at a faster rate right on to 69 DAE at the expense of RGR which reached a local minimum. The index however rose again to a local maximum 81 DAE as a result of the improving moisture condition. After that harvest ontogeny dictated in the decrease of all the organs.

The 1992 RGR for the non-irrigated combination of C. quinoa (fig. 12(II)) dropped from 0.1 in the second harvest. The appearance of the inflorescences and the poor moisture condition might have caused the decrease in the index. The decrease continued and reached its lowest value 69 DAE. The index again started to rise with the improvement in moisture condition around 81 DAE. The contribution of all the organs to RGR except the inflorescence increased. After the fifth harvest the index was somewhat stable thanks to the improved rainfall condition. It should be added that the index underwent little variation in its course.

In 1993 the RGR curve (fig. 13(I)) of the irrigated combination of A. cruentus started by falling. The situation might not be unconnected with low precipitation around 11DAE. After 42 DAE the curve rose again probably due to improved rainfall condition as manifested by a high hydrothermal index for the better part of late June preceding the harvest on the 12th of July, 52 DAE.

The harvest on the 22 of July, 62 DAE reavealed a fall in the RGR. The contribution of all the organs to RGR fell. The next harvest 72 DAE revealed a rise in RGR. This may be due to optimum moisture condition. Even the appearance of stronger acceptors as the inflorescences did not cause a reduction in RGR. The next harvest 82 DAE revealed a fall in the index. This phenomenon might not be unconnected with the continued depreciation of the moisture condition. The harvest on the 21st August 92 DAE revealed RGR reaching a local maximum. This may be attributed to improved moisture condition. After that harvest ontogenetic drift caused the fall of the index. The harvests at 102 and the last at 112 DAE all recorded a fall in RGR.

The non-irrigated combination of A. cruentus (fig. 13(II)) rose after the second harvest 32 DAE apparently taking advantage of the condusive moisture condition. After 32 DAE the index was still rising infact reaching its maximum value 52 DAE. Indeed the hydrothermal index reached the maximum value of over 2.8 around 52 DAE after that the index started to fall. The fall recorded 62 DAE might be due to the depreciative moisture condition as manifested by the falling hydrothermal index before the harvest. The contribution of the branches to RGR during the 6th harvest, 92 DAE, was two folds. First, the branches were about 38% of the total DM of plant (fig.23 (II)). Futhermore the fresh assimilatory surface of branches provided improvement in net assimilation which in turn improved biomass accumulation. The contribution of the branches to the RGR 72 DAE outweighed the effect of the depreciating moisture condition which was clearly shown by the hydrothermal index. The said contribution of the branches also made trivial the negative effect of the appearance of the inflorescences which is usually reflected on RGR. Anyway the harvest at 82 DAE revealed the negative effect that the continued depreciating moisture condition had on RGR. Indeed the contribution of all the organs was affected. The 8th harvest, 92 DAE, revealed improvement in RGR, which reflected the improving moisture condition. Indeed the index reached a local maximum after that ontogenetic drift caught up with the index.

The RGR for the irrigated combination of C. quinoa in 1993 figure 14(I) started by falling. It was all the time falling. Even the condusive conditions of growth and development existing during the 4th harvest, 52 DAE, did not stop the index from falling. Improved moisture conditions are sometimes accompanied by an improvement in RGR. Probably the appearance of inflorences coupled with depriciating moisture conditions caused the reduction in RGR 72 and 82 DAE. In the 8th harvest, 92 DAE, when ontogentic drift had already caught up with the index not even the gain manifested by the contribution of the leaves coupled with improved moisture conditions remedied the downfall of the index.

In 1993 the RGR for the non-irrigated combination of C. quinoa (fig. 14(II)) initially rose after the 2nd harvest 32 DAE. This may be due to the contribution of the leaves. The moisture condition was also favourable. The crops utilized the condusive moisture condition in further raising the index 42 DAE. In the 4th harvest, 52 DAE, utilization of the increased rainfall resource was also manifested through the rise in RGR. The 5th harvest, 62 DAE, revealed a reduction in the index which might have been a reflection of the depreciating moisture condition. The 6th and 7th harvests, 72 and 82 DAE respectively revealed a continued fall in the index as verification of the depreciating moisture condition. The 8th harvest, 92 DAE, revealed a local maximum probably reflecting the improvement in moisture, before the setting of ontogenetic drift during the 9th harvest, 102 DAE.

ULR

The 1992 ULR for the irrigated combination of A. cruentus initially fell (fig. 15(I)) between the 2nd and the 3rd harvests 38 and 49 DAE. The non-irrigated combination also followed the same trend. This may be due to the difficulty of crop establisment as a result of moisture stress earlier-mentioned in section 2.3 of the methodology. Only once around 12 DAE, did the hydrothermal index reached unity. The curves for the two combinations rose between 49 and 59 DAE. The two curves merged 59 DAE. The reason for the rise in the curve when the moisture condition around the harvest 49 and 59 DAE was depreciating might be associated with robustness in growth and development after the second fertilizer application 55 DAE. The continued moisture stress beyond 59 DAE out-weighed earlier positive effects of the fertilizer application and so the curve fell steeply in both combinations with the irrigated reaching a local minimum value 70 DAE which was lower than the minimun of the non-irrigated combination. The curve for the irrigated combination did not change 79 DAE, while that for the non-irrigated rose to a local maximum. It is possible that 79 DAE witnessed the threshold to improvement in the moisture regime. Indeed the next harvest revealed a tremendous rise in the curve of the irrigated combination which reached its maximum before the onset of ontogenetic drift. The non-irrigated combination however fell slightly 91 DAE but rose steeply again 99 DAE, obviously taking advantage of the improved moisture regime around 101.

The rise in the index of the non-irrigated combination 99 DAE was significant. In most crops ontogeny might have caught up with the index. A. cruentus has the specific characteristic of possessing lots of green leaves during the late vegetative season. The said leaves are usually as efficient in assimilation as those during earlier stages of development.

The ULR in the irrigated combination of C. quinoa in 1992, (fig. 15(II)) fell between 52 to 61 DAE. The rise of the curve by the non-irrigated combination during the same period was also somewhat not clearly defined, with a gradient that is minimal. The situation might have reflected the low moisture regime during the period between the last decade of July, around 70 DAE and the end of the first decade of August, after 79 DAE. Indeed to substantiate the claim that waterlessness was a major factor in the poor showing of the index, both curves dropped during the period 61 and 69 DAE. During that period the hydrothermal index was below 0.5, signifying too little water for growth and developmental processes. After that, the period between 69 and 81 DAE revealed increases in both curves. The significance of the rise was in the steepness. The non-irrigated combination was rising from its lowest point. The rise coincided with the time in which the moisture regime started to improve during the second decade of August , around 80 DAE. During the period between 81 and 89 DAE the curve of the irrigated fell while that of the non-irrigated rose. The same trend continued during the period between 89 and 102 DAE. A plausible reason for the trend might be that 81 DAE the curve of the irrigated combination attained its highest level after which ontogeny caught up with it. It is possible that by that time the non-irrigated combination was benifiting from the high moisture level during the last decade of August, around 95 DAE and the first decade of september to optimize its growth and developmental processes, which were not fully realized during earlier stages of growth because of moisture stress experienced in 1992.

In 1993 the curve of the irrigated combination of A. cruentus fell (fig. 16(I)) during the period between 32 and 42 DAE. By then the curve of the non-irrigated combination was rising, reaching a local maximum 52 DAE. During the period 42 to 52 DAE the curve of the irrigated combination also rose. The improved moisture condition during the period between the 1st and 2nd decades of July, around 50 DAE might have in turn caused the improvement in ULR. Between 52 and 62 DAE the curve again fell. The moisture regime during the second decade corresponding to the period when the curves fell, was depreciating it is therefore plausible to suggest a cause and effect relationship. The curves again rose after 62 DAE. It is possible that the appearance of the generative organ, the inflorescence, may have put a high premium on the index. Indeed the curves reached their peaks 72 DAE. However, probably because of continious depreciation of the moisture regime, the curves fell between 72 to 82 DAE. When the moisture regime again improved during the period between 82 and 92 DAE, the curves again rose steeply. While the curve for the irrigated combination continued rising during the next period between 92 and 102 DAE, ontogeny caught up with the non-irrigated combination. Ontogenetic drift caught up with the irrigated combination after the harvest on the 21st August, 102 DAE.

In 1993 the ULR for the irrigated combination of C. quinoa (fig. 16(II)) was initially stable during the period between 32 and 42 DAE. The curve for the non-irrigated combination rose during the same period. The plants might have benefited from the conducive moisture condition prevalent at the time. The next period between 42 and 52 DAE revealed a rise in the curve for the irrigated combination and a further rise in the curve for the non-irrigated combination infact reaching its maximum 52 DAE. The non-irrigated unlike the irrigated combination tremendously benefited from the favorable moisture regime prevalent during this period. The ULR of the irrigated combination might have depreciated due to having an enormous non-assimilatory fraction, which put a heavy load on the assimilatory fraction.

During the period between 52 and 62 DAE ULR of irrigated plants was increasing while that of the non-irrigated ones was falling. The period between 62 and 72 DAE revealed a rise in the index for both combinations. This may be due to the appearance of the inflorescences, which usually put a high premium on the ULR. The next period between 72 and 82 DAE revealed arise in both combinations. During the period between 82 and 92 DAE the curve of the irrigated combination fell steeply suggesting the on-set of ontogeny. The non-irrigated combination on the other hand rose to a local maximum 92 DAE before the on-set of ontogeny. It may have benefited from the favourable moisture condition. Despite the favorable moisture condition during the period between 92 and 102 DAE the non-irrigated combination dropped while the irrigated combination rose. In both cases ontogeny was the most plausible reason.

LWR

In 1992 the LWR curves (fig. 17(I)) for the irrigated and non-irrigated combinations of A. cruentus were similar in their course. They were inversely proportional to time. They were subjected to ontogeny. The values of the non-irrigated combination were higher at 49, 59, 91 and 99 DAE. The curves for the irrigated and non-irrigated combinations of C. quinoa in 1992 (fig 17(II)) also showed the same ontogenetic tendency as in the case of A. cruentus. The main difference was that in the case of C. quinoa the non-irrigated combination had higher values throughout.

In 1993 LWR (fig. 18) was also not very dissimilar in its course in both species and combinations to that in 1992. First, like in 1992 the index was subjected to ontogenetic drift in both combinations and species. Secondly the non-irrigated combination was higher in values during most harvests in both species. It is possible that the greater contribution of the non-assimilatory organs, like the stems, in the irrigated treatment might be due to preparation for carrying the relatively heavier assimilatory and generative organs. It should not go without observation that even when the irrigated had higher values like in the case of C. quinoa in 1992, this situation was only temporary and was later inverted. This may suggest that the addition of biomass to the non-assimilatory organs, like the stem, might have been necessary in preparation for the heavy assimilatory and generative organs which they had to carry.

In the case of A. cruentus a C4 species, the range of the values of LWR was somewhat similar in both combinations and years, fetching between 0.1 and 0.75. In C. quinoa, a C3 species characterized by its relatively heavier dependence on water, the situation was markedly different. The LWR was markedly dissimilar between the two years which may be due to tremendous differences in moisture condition. The index fetched values between 0.03 and 0.27 in 1992 while in 1993 the range was between 0 and 0.65. In 1993 the relatively favorable moisture condition might have been benefited from by both combinations in realizing higher values of the index.

SLA

In 1992 SLA for the irrigated combination A. cruentus initially fell, (fig 19(I)), reaching its minimum, 70 days after emergence before it started to rise again. The non-irrigated combination on the other hand initially rose reaching a local maximum 49 days after emergence before falling gently to a minimum 91 days after emergence. The curves of both combinations did not vary widely during the course of the cropping season. This observation is normal. The fact that the curve of the non-irrigated combination was for most times higher in value may not be unconnected with the further fact that irrigation promoted higher biomass accumulation. In 1992 the SLA of C. quinoa, (fig. 19(II)) did not vary much in both combinations. The lowest values for the irrigated and the non-irrigated combinations were in the 4th harvest 69 DAE. This might have reflected the waterlessness that had being prevailing. The fact that the index for the irrigated combination was higher 61, 69 and 81 DAE may be due to the appearance of many new leaves that were thinner due to constant irrigation.

The SLA indices for the irrigated and non-irrigated combinations of A. cruentus in 1993, figure 20(I), initially dropped steeply. Beyond 42 DAE they did not vary much right through to the end of the cropping season. The moisture regime was comparatively better than in 1992. This might be the reason why an inversion of the 1992 situation, with the irrigated having higher values for most of the time, was the case. The sufficiency in rainfall was somewhat benefited from by both combinations by way of biomass accumulation. The additional irrigation might have caused the higher assimilatory surface area values in the irrigated combination. The higher quotients (SLA) were then justified in accordance with the formula in section 2.3 of chapter two.

In the two combinations of C. quinoa in 1993, (fig. 20(II)), the SLA curves were rising all the time. The obvious variation in the course of the index during the cropping season might be attributed to the favourable moisture condition in 1993. The irrigated combination had higher values for the better part of the cropping season. This might be attributed to the increase in assimilatory surface area due to the improved moisture condition.

LAR

The courses of the leaf area ratio (LAR), which is the product of the SLA and LWR, for the two years of field experiment 1992 and 1993, are displayed as (fig 33 and 34) respectively. In (fig. 33 (I) and (II)) both curves fell implying an inverse relationship with time. In general the non irrigated had the higher values.

In (fig. 34 (I)) the relationship also implies indirect variation between DAE and LAR, between 72 and 112 DAE the irrigated treatment had the higher values. In (fig. 34 (II)) inverse variation was also shown but the non-irrigated had higher values.

Percentage contribution of organs

In 1992 and 1993 the contribution of the leaves to the dry matter (DM) was initially very high in both the irrigated and the non-irrigated combinations of A. cruentus, (fig. 21 and 23) respectively. The contribution of the non-assimilatory organs was relatively smaller. The assimilatory apparatus systematically decreased as the cropping season proceeded while the other non-assimilatory organs, like the inflorescence and seeds, which were produced during late development increased their contribution. The stems, generally, displayed a monomodal type of curve. Initially its contribution was small it later increased its contribution towards the middle of the cropping season. This may be in preparation of having to carry a heavy load of both assimilatory and generative organs. Its contribution however declined towards the end of the cropping season when the generative organs increased.

In C. quinoa, two distinct patterns of percentage contribution of organs to DM based on cropping season were observed. In 1992, (fig. 22), which was drier the contribution of the leaves, petioles and the branches as assimilatory organs was relatively smaller than the contribution of the stems. In 1993, (fig. 24), the situation was a reversal of the 1992 observation. In both patterns, systematic decrease of the percentage contribution of the assimilatory apparatus with an increase in the percentage contribution of the generative organs was observed. The stems revealed the same progress as in A. cruentus. The observed decreased percentage contribution of the assimilatory surface in C. quinoa in 1992 may be due to the strategy of evading excessive transpiration losses. The reduced percentage contribution may have been at the benefit of the roots. Usually when a resource is limited, in the case of 1992 it was moisture, the organ that is charged with the function of supplying that resource will increase its development and growth relative to the others, inorder to meet the needs of the plant in that resource.

Crop Growth Rate (CGR)

The CGR for the irrigated combination of A. cruentus during the 1992 cropping season (fig 25(I)) rose from the second harvest 38 DAE. During the same period the non-irrigated combination curve was stable. The succeeding period between 49 and 59 DAE revealed a steep rise in both curves. This may not be unconnected with the improved moisture condition. Both curves reached local maxima 59 days after emergence with the irrigated combination having the higher value. The period between 59 and 70 DAE revealed a steep fall in the curves. This period corresponded with depreciating moisture condition. Indeed the non-irrigated combination reached its minimum at the end of this period. The next period between 70 and 79 DAE revealed stability in the curve of the irrigated combination while the non-irrigated curve made a somewhat slight upward rise. There was a slight improvement in the moisture but this was not benefited from immidiately probably due to the fact that inflorescence appeared 70 DAE. The appearance of these non-assimilatory stronger acceptors during this period might have led to the retardation in growth of the other organs that are primary producers like the leaves, branches and petioles. During the period 79 and 91, the index of the irrigated combination again rose steeply while that of the non-irrigated was stable. The irrigated combination obviously led in benefiting from the improved moisture condition which reached a maximum at the end of this period. The non-irrigated combination might have had the added problem of coping with seed development. This might have caused the delay in its response to the improved moisture during this period. Indeed the seeds appeared 91 DAE. The development of the seeds which are non-photosynthesizing might have led to lateness in response to the improved moisture by other assimilatory organs in the non-irrigated combination. In the irrigated combination the situation was different due to mentainance of stability through constant irrigation. The irrigated combination having reached its maximum 91 DAE fell steeply to as low as -32 g g-1 day-1 during the last harvest 99 DAE. It was during this same period that the non-irrigated combination then benefited from the improved moisture. This was shown by the steep rise of its curve to a maximum.

The CGR for the irrigated combination of C. quinoa in 1992 (fig. 25(II)) declined during the period between 52 and 61 DAE while the non-irrigated rose with a somewhat small gradient. The situation might be a reflection of the depreciating moisture condition. To substantiate this claim both curves declined during the period 61 and 69 DAE with the non-irrigated reaching its minimum. Furthermore the development of inflorescence in the buds might have added to the low moisture effect during this period. Indeed the inflorescence appeared 61 DAE. The following period between 69 and 81 DAE revealed a rise in the index in both combinations. This may be due to the fact that the improving moisture condition led in turn to an increase in the contribution of the assimilatory apparatus. This fact was manifested by the increased contribution of the leaves branches and petioles to RGR. During the period 81 and 89 DAE the curve of the irrigated combination fell while that of the non-irrigated combination rose with a small gradient. The non-irrigated combination may have benefited from the improved moisture. The irrigated on the other hand may have benefited from irrigation and reached its maximum 81 DAE. Until the time when strong winds blew down the plants 102 DAE. By then CGR in the irrigated combination was still falling while it was still rising in the non-irrigated combination.

In 1993 the CGR in the irrigated combination of A. cruentus (fig. 26(I)) during the period between 32 and 42 DAE somewhat rose with an almost indiscernible gradient. The gradient of the curve of the non-irrigated combination was also small. During the period between 42 and 52 DAE, both curves rose. The contribution of the assimilatory apparatus in the form of the leaves and petioles increased as manifested by the RGR curve. The successive period between 52 and 62 DAE revealed stability in both curves. This situation may have been caused by the decrease in the contribution of the assimilatory apparatus as indicated by the RGR curves (fig. 13). Indeed the period between 62 and 72 DAE revealed a rise in both CGR and the contribution of the assimilatory apparatus as indicated by RGR. The irrigated combination had the higher value in CGR, infact reaching a local maximum at the end of this period. This period also recorded a hydrothermal index, on the average, of about 0.6. The significance of this fact to the growth characteristics lies in the further fact that the reduction of the moisture relative to the previous period may have led to field capacity moisture around the root zone. The generative organ, the inflorescence, also appeared at the end of this period. Notwithstanding the appearance of these strong non-assimilatory organ CGR rose in both combinations. This may have indicated that soil moisture was optimum. However with decreasing moisture level during the period between 72 and 82 DAE, CGR dropped. The contribution of the assimilatory apparatus also dropped, suggesting that it might have caused the drop in CGR.

The next period, 82 to 92 DAE, revealed a rise in the index in both combinations with the non-irrigated having the higher value. The situation may have reflected the improving moisture condition. The higher value manifested by the non-irrigated combination may be more clearly understood from the point of view of the increasing contribution of the branches. It should be noted that in the non-irrigated combination notwithstanding the fall in the contribution of the leaves to RGR, the index still rose. This might have been due to the fact that the branches played a leading role in the assimilatory apparatus. The following period between 92 to 102 DAE, the index of the irrigated combination rose while that of the non-irrigated fell steeply. The development of the seeds may have caused the drop in the index in the non-irrigated combination, while the irrigated benefited from the subsidized irrigation to increase its RGR. Indeed the seeds appeared at the end of this period. The period between 102 and 112 DAE revealed a fall in the index of the irrigated while that of the non-irrigated combination rose. The irrigated curve fell probably because the index had reached its maximum while the non-irrigated combination benefited from the improved moisture condition.

The CGR of the irrigated combination of C. quinoa during the 1993 cropping season (fig. 26(II)) rose initially during the period within 32 and 42 DAE. The same was recorded for the non-irrigated combination. The irrigated combination had higher values. The same upward trend was recorded for the period between 42 and 52 DAE. During the period 52 and 62 DAE, CGR of the irrigated combination rose while that of the non-irrigated combination fell with a somewhat small gradient. The next period between 62 and 72 days after emergence revealed a further steep rise in the index of the irrigated combination while that of the non-irrigated rose with a small gradient. The successive period between 72 and 82 DAE revealed a further rise in the index of the irrigated combination while the index of the non-irrigated fell slightly. This may be due to low moisture level as indicated by the falling hydrothermal index. The development of the seeds which indeed appeared at the end of this period may have compounded the low moisture problem in the non-irrigated combination while the irrigated was late to respond due to irrigation. The period between 82 and 92 DAE revealed a fall in the index of the irrigated combination. The situation might be due to the on-set of ontogeny. The contribution of the assimilatory apparatus was of little importance as the organs involved were probably too old to be efficient enough. This claim was substantiated by the ULR curve which dropped steeply. The CGR curve for the non-irrigated treatment rose during this period probably due to beneficial effects of the improved moisture condition. At the end of this period ontogeny also caused a drop in the index.

Unit Leaf Rate of canopy (ULRc)

The ULRc of the irrigated combination of A. cruentus in 1992, (fig. 27(I)), fell during the period between 38 and 49 days after emergence. The same progress was recorded for the non-irrigated combination. Although both curves fell to local minima that of the irrigated combination was higher in value at the end of the period under review. The fall in both curves was a reflection of the low moisture condition initially encountered at the beginning of the cropping season. The period between 49 and 59 DAE revealed a rise in the indices of both combinations. The crops may have had a belated response to the improved moisture condition. However with increasing depreciation in moisture, both curves fell again between 59 and 70 DAE, with the irrigated having the least value at the end of the period. The successive period between 70 and 79 DAE revealed a rise in the curve of the non-irrigated while that of the irrigated was stable. Due to improved moisture condition during the period 79 and 91 DAE, the ULRc of the irrigated combination rose markedly. The non-irrigated combination however failed to show an early start in benefiting from the improved moisture condition. The ULRc of the irrigated combination having reached its maximum at the end of the period, started falling while the non-irrigated started to rise. The non-irrigated might have shown signs of a belated response to the improved moisture condition.

The ULRc of the irrigated combination of C. quinoa in 1992, (fig. 27(II)) started by falling during the period 52 and 61 DAE while that of the non-irrigated rose with a somewhat small gradient. Indeed the next phase between 61 and 69 DAE clearly showed the negative effects of the low moisture level at the beginning of the cropping season. Both curves fell with the non-irrigated reaching its minimum value at the end of the period. During the next period between 69 and 81 DAE the indices of both combinations rose steeply. This may have been due to the improved moisture condition. The next period between 81 and 89 DAE the curve of the irrigated fell steeply after reaching a maximum, at the same time that of the non-irrigated rose. The irrigated combination may have reached its maturity while the non-irrigated benefited from the improved moisture condition.

The ULRc of Amaranth in 1993 followed the same pattern independent of soil moisture treatment. The maximum value attained at 72 DAE was about 12 for the non-irrigated, while that of the irrigated was about 10 g g-1 day-1. The only significant difference between both treatments was after 82 DAE. The values for the irrigated plants displayed diverse time course, reaching 2 at the end of the experiment, while in the non-irrigated treatment it was more than 6.

ULRc of the irrigated quinoa started at 8 g g-1 day-1 32 DAE and stabilized between 62 and 82 DAE and it reached a maximum of 9,42 DAE. Non-irrigated plants of quinoa sharply increased their ULRc during 32 and 52 DAE. They reached maximum of about 10,5 g g-1 day-1 52 DAE, but steeply decreased to about 4 82 DAE, probably following an abundance of rainfall (see Selyaninov index). Nevertheless the subsequent drop of ULRc in the treatment resulted in values of the index below 2 g g-1 day-1.

Leaf Area Index (LAI)

The LAI of A. cruentus of both the irrigated and non-irrigated combinations in 1992, (fig 29(I)) was rising between 38 and 70 DAE. Later probably due to senescence and abscission of older leaves which were replaced by smaller and younger leaves due to reduced moisture level the curve dropped slightly between 70 and 79 DAE for the non-irrigated combination and was stable for the irrigated combination. The curve again rose in the irrigated combination between 79 and 91 DAE at the same time the curve of the non-irrigated combination remained stable. Later between 91 and 99 DAE both curves rose with the non-irrigated having the steeper gradient. It may have followed in benefiting from the improved moisture condition. The irrigated combination curve already started to rise during the earlier period between 79 and 91 DAE. The fact that LAI rose between 91 and 99 DAE was significant in the sense that the tendency of A. cruentus to keep green leaves even when most of the seeds are matured and ready for harvest was exhibited.

The LAI for C. quinoa in both the irrigated and non-irrigated combinations in 1992 (fig. 29(II)) initially rose between 52 and 61 DAE. Both combinations had maximum values 61 DAE. The continued depreciation of the moisture condition caused a fall in the indices between 61 and 69 DAE. The unfavourable moisture led to further decrease in the index of the non-irrigated while the irrigated rose between 69 and 81 DAE. The differences between combinations may be due to the fact that the irrigated was receiving additional moisture. Between 81 and 89 DAE the same trend as in the previous period continued although the non-irrigated somewhat had a gradient that was smaller than that of the previous period. Indeed the period between 89 and 102 DAE almost failed to reveal any fall in the index of the non-irrigated, probably due to the fact that the plants responded to the improvement in moisture. The irrigated on the other hand fell probably due to ontogeny.

In 1993 the index of the irrigated combination of A. cruentus, (fig. 30(I)) rose right through to its maximum value 102 DAE before it fell due to ontogeny. The index of the non-irrigated also rose though with lesser values relative to those of the irrigated. The index of the non-irrigated might have shown that the plants benefited from the improved moisture at the end of the cropping season. Proof of this was in the fact that even when the index of the irrigated fell that of the non-irrigated rose between 102 and 112 DAE. The curve of LAI (fig. 30(II)) of the irrigated combination of C. quinoa rose right through to the last harvest 102 DAE. The non-irrigated combination also followed the same trend, though with lesser values, right through to the 8th harvest 92 DAE. After that harvest the index fell slightly 102 DAE.

It should be noted that the LAI of both combinations and species during most harvests was increasing. Except for the 1992 C. quinoa, (fig. 29(II)), most combinations had values greater than five which falls within the expected norms for temperate crops.In (Fig. 31 and 32) the leaf area duration (LAD) for the two combinations and species during the two cropping seasons 1992 and 1993 respectively are displayed. Chenopodium quinoa had higher values in both combinations than A. cruentus in 1993 but lesser in both combinations in 1992. This observation probably underlines the importance of water to C3 carboxylation pathway plants. Indeed in 1993 the moisture conditions were better than in 1992 hence the better showing in the index for C. quinoa, a C3 pathway plant, in 1993 than in 1992.

Harvest Index (HI)

The means of A. cruentus in both combinations in the 1992 plot experiment were 0.19 and 0.36 for the irrigated and non-irrigated combinations respectively. While they were 0.16 and 0.19 in 1993 in the same order as in 1992. The means for C. quinoa were 0.19 and 0.16 in 1992 for the irrigated and non-irrigated combinations respectively. While they were 0.16 and 0.19 in 1993 in the same order as in 1992. It is timely for ease of comparison to include the HI results for the pot experiment in 1992. The A. cruentus means were 0.46 and 0.48 for the high and low soil moisture levels respectively while they were 0.57 and 0.48 for C. quinoa in the same respective order as for amaranth.

Analysis of variance (ANOVA) revealed highly significant differences between species, combinations and their interaction in the HI of the 1992 and 1993 plot experiments. In 1992 A. cruentus had the higher value of 0.29 while C. quinoa had 0.19 with LSD equal 0.01. The non-irrigated combination had the higher value of 0.29 while the irrigated had 0.19 with LSD equal 0.01. In 1993 the 0.18 mean of A. cruentus compared favourably to the 0.13 value of C. quinoa with LSD equal 0.01. It should be noted that with respect to 1993 the 0.18 value of the irrigated combination compared favourably to the 0.13 value of the non-irrigated combination. The least significant difference (LSD) was 0.01. This was contrasting to the 1992 results. Comparison between cropping seasons revealed significant differences. The 0.23 mean of 1992 compared favourably to the 0.16 value of 1993 with LSD equal to 0.06.

Comparison between plot and potted experiments in 1992 were based on the two moisture levels. The results of the high moisture level combination of the pot experiment were compared with the irrigated combination of the plot experiment. Highly significant differences were found between species while significant differences were found between experiments (plot x pot) and the interaction of the two factors. The mean of A. cruentus was 0.18 while that of C. quinoa 0.52. The plot experiment had a mean of 0.33 and that of the pot 0.38. The least significant difference (LSD) was 0.04 in both cases.

Analysis of variance (ANOVA) was also carried out between the low moisture combination of the pot experiment and the non-irrigated combination of the plot experiment in 1992. It revealed highly significant differences between species, experiments (plot versus pot) and their interaction. The mean of A. cruentus was 0.49 while it was 0.29 for C. quinoa. The mean of the plotted experiment was 0.29 while that of the potted was 0.49. The LSD in both cases was 0.01.

It should not pass without observation that specific differences depend on the moisture level. When the high moisture level combination was compared with the irrigated combination the mean of C. quinoa (C3 plant) compared favourably to the mean of A. cruentus (C4 plant). On the other hand, when the low moisture combination of the pot experiment was compared with the non-irrigated combination A. cruentus compared favourably to C. quinoa. This further underlines the relatively higher water use efficiency (WUE) of A. cruentus (C4). The differences in the level of significance between the experiments and their interactions is also worthy of notice.

MINERAL RELATION

CRUDE PROTEIN (CP)

In 1992 comparison between species for the irrigated treatment of the first harvest (tables 14 and 15), revealed that amaranth had the higher value for branches while quinoa compared favourably in the leaves and seeds. Between species comparison, for the non-irrigated treatments, revealed that quinoa had the higher values for all the organs.

The second harvest revealed that the irrigated quinoa had the higher value of leaves but amaranth was observed to have higher ones for the branches and seeds. The non-irrigated treatment of the second harvest revealed that quinoa compared favourably in the case of the leaves, seeds and stems while amaranth had the higher values for branches.

Between soil moisture treatments comparison, (table 14) in 1992 for the first harvest revealed that the non-irrigated had the higher value for % CP while the second harvest revealed that they compared favourably in the branches leaves and stems.

In (table 15) between soil moisture treatments comparison showed higher %CP values of the branches and seeds for the non-irrigated in the first harvest. The second harvest showed that the irrigated had the higher values of % CP for branches while the non-irrigated had the higher values for the rest of the other organs.

In 1993 between species comparison for the first harvest of the irrigated treatment revealed that the leaves and stems of quinoa had more % CP while the seeds of amaranth had the higher values. Comparison for the non-irrigated treatment of the first harvest showed that amaranth had the higher value for the seeds only while quinoa had the higher values for the rest of the other organs.

In the second harvest of the irrigated treatment in 1993, quinoa showed higher % CP values than the branches, leaves and stems. In the second harvest of the non-irrigated treatment quinoa had higher values in all but the seeds.

In (table 16) comparison between soil moisture treatments in the first harvest revealed that the irrigated had the higher % CP in the branches. The same was observed in the second harvest. In (table 17) comparison between soil moisture treatments in the first harvest showed that the leaves and branches of the non-irrigated had a slightly higher % CP value. The second harvest also showed slightly higher % CP alnes for branches, leaves and stems.

Ca

In 1992 comparing the species in the first harvest for the irrigated treatment revealed that quinoa had the higher values for the leaves and stems while the non-irrigated showed higher Ca values of amaranth for all the organs investigated except seeds.

Companing the irrigated treatments in the second harvest between species revealed that amaranth had higher values in all but the seeds while in the non-irrigated it had higher values in all the organs.

In table I4 comparison between moisture treatments in the first harvest showed slightly higher values of Ca in the leaves of the non-irrigated treatment. Comparison in the second harvest also showed a slightly higher value of Ca for the irrigated treatment.

In (table 15) between soil moisture comparison showed that the non-irrigated had higher values in all but the branches during the first harvest, while the second harvest revealed higher values for the branches and leaves of the non-irrigated but the seeds of the irrigated had the higher value.

In 1993 between species comparison in the first harvest for the irrigated treatment showed higher Ca values in all the organs of amaranth relative to quinoa. Comparison in the non-irrigated revealed the same result as in the irrigated.

During the same year, 1993, between species comparison in the irrigated of the second havest revealed higher values in all but the seeds for amaranth, while the comparison between species of the non-irrigated in the second harvest showed that amaranth had higher values of Ca in all the organs.

In (table 16) between soil moisture treatments in the first harvest revealed that the non-irrigated had the higher values for branches and leaves while the second harvest showed higher values of Ca for branches and stems of the irrigated but higher for the non-irrigated for seeds and leaves.

In (table 17) between soil moisture treatments comparison in the first harvest showed the irrigation leaves to be higher in Ca while second harvest showed the non-irrigated to be higher for the leaves and the irrigated to be slightly higher in the branches.

P

In 1992 between species comparison in the first harvest for the irrigated did not reveal substantial differences. The same was observed for the non-irrigated.

In 1992 between species Comparison in the second harvest did not reveal any differences in the irrigated treatment while as slightly higher values were shown in the non-irrigated of amaranth in the seeds.

In (table 14) between soil moisture comparison in the first harvest showed that the non-irrigated was slightly higher in P for the seeds, while the second harvest revealed no substantial differences.

In (table 15) comparison between soil moisture treatments in the first harvest revealed a slightly higher value for the non-irrigated in the seeds, while no substantial difference was abserved in the second harvest.

In 1993 between species comparison in the first harvest of the irrigated revealed slight differences in the leaves with amaranth having the higher value. The stems of quinoa were however found to be slightly higher in the value. In the non-irrigated for the first harvest amaranth had the higher values in the branches and the leaves, while quinoa stems had slightly higher values.

In the second harvest of the irrigated treatment, quinoa had slightly higher P in the leaves while the value of P was slightly higher in the stems of amaranth. In the non-irrigated treatment of the second harvest quinoa had higher values in branches and leaves, while amaranth had slightly higher value for the stems.

In (table 16) comparison between soil moistue treatment in the first harvest did not reveal any substantial differences.The same was observed during the second harvest.

In (table 17) the first harvest showed the branches and leaves of the non-irrigated to be slightly higher in P than the irrigated. During the second harvest no substantial differences were observed.

K

In 1992 between species comparison for the first harvest of the irrigated treatment showed substantial differences with quinoa having higher values for all the organs investigated. The non-irrigated also showed differences with quinoa clearly having the higher value for all the organs. In the second harvest of the irrigated treatment quinoa also had the higher value in K. In the non-irrigated quinoa led in all but the stems.

In (table 14) between soil moisture comparison in the first harvest showed that the branches of the irrigated had the higher value. In the second harvest the stems of the non-irrigated showed higer values for K, while the branches of the non-irrigated had higher values for amaranth.

In (table 15) the non-irrigated had higher values in all but the leaves during the first harvest, while the irrigated had the higher value in all the organs during the second harvest.

In 1993, between species comparison for the first harvest of the irrigated treatment showed quinoa to have higher values in all the organs except the stems. The same was observed for the non-irrigated of the first harvest and the second harvest of the irrigated. The second harvest of the non-irrigated quinoa had higher values for the branches and stems, while amaranth had higher K values for the leaves and seeds.

In (table 16) between soil moisture treatments comparison for the first harvest revealed that the irrigated had higher values for all the organs. The second harvest showed that the irrigated had higher values for the stems, while the non-irrigated had the higher one for the leaves and branches.

In (table 17) between soil moisture comparison in the first harvest showed the non-irrigated to be higher in values for the leaves and stems while the irrigated had the higher values for the branches. In the second harvest the irrigated had higher K values for all the organs investigated.

Mg

In 1992 comparison for the first harvest of the irrigated combination showed that amaranth had slightly higher values for the leaves and stems, while quinoa had slightly higher ones for the branches and seeds. In the non-irrigated treatment amaranth had slightly higher values for the branches and leaves while quinoa was observed to have a slightly higher Mg for the seeds.

During the second harvest the leaves of amaranth were observed to have the higher value for the irrigated while no substantial differences were found in the non-irrigated combination.

In (table 14) between soil moisture treatmentss comparison showed that the branches and stems of the non-irrigated were higher in Mg while the stems of the irrigated had the higher value for the first harvest. During the second harvest the irrigated had the higher value for the leaves.

In (table 15) comparison between soil moisture in the first harvest revealed no substantial differences. The same was also observed for the second harvest.

In 1993 comparison between species in the first harvest revealed that the stems of amaranth had higher Mg values in both irrigated and non-irrigated. The second harvest revealed that the stems of irrigated quinoa had the slightly higher value while the stems of the non-irrigated amaranth again had higher value in that harvest. In (table 16) between soil moisture treatments comparison revealed no substantial differences in the first harvest. In the second harvest the leaves of the irrigated had the higher value while the non-irrigated had the higher value for the seeds.

In (table 17) no substantial differences were found in the first harvest between soil moisture treatments comparison. In the second harvest the seeds and branches of the irrigated treatment had the higher value.

Zn

In 1992 between species comparison in the first harvest for the irrigated treatment revealed that amaranth had the higher value for the stems and the leaves. It also had the higher values for the branches, leaves and stems for the nor the non-irrigated treatment. The second harvest revealed higher values for all the organs of amaranth for the irrigated treatment. The same was observed for the non-irrigated treatment.

In (table 14) between soil moisture comparison for the first harvest revealed that the non-irrigated had the higher values in all organs but the stems, while the second harvest revealed the irrigated to have the higher values in all the organs.

In (table 15) the irrigated had slightly higher values than the non-irrigated in the branches and the leaves for the first harvest while it had the higher values for all the organs in the second harvest.

In 1993 comparison between species in the first harvest for the irrigated treatment revealed that amaranth had the higher values in all organs but the leaves. The same was observed for the non-irrigated treatment. The second harvest of the irrigated revealed that amaranth had the higher values in all the organs. In the non-irrigated treatment it had the higher values in all but the leaves.

Comparison between soil moisture treatments, (table 16), revealed that the irrigated had the higher values in all the organs for the first harvest, while the second harvest revealed that the non-irrigated had the higher values in all but the seeds.

In figure 17, between soil moisture treatmentss comparison in the first harvest revealed that the irrigated had the higher values in all the organs while the second harvest showed that the irrigated had higher values in the case of branches but the non-irrigated had the higher value for the leaves.

Cu

In 1992 comparison between species for the first harvest in the irrigated combination showed that amaranth had the higher value for the branches while quinoa had slightly higher ones for the leaves and the stems. The non-irrigated treatment revealed that quinoa had the higher value in the organs.

The second harvest of the irrigated treatment showed that amaranth had the higher values for the branches and the seeds while quinoa had the higher value for the leaves and the stems. In the non-irrigated amaranth had the higher value only in the branches while quinoa had the higher values for the rest of the other organs.

In (table 14) between soil moisture comparison in the first harvest revealed that the irrigated had the higher values in all the organs, while the non-irrigated had the higher values in all organs for the second harvest.

In (table 15) comparison between soil moisture treatmentss in the first harvest revealed that the non-irrigated had higher values for all the organs, while it had higher values in the leaves only for the second harvest.

In 1993 comparison between species for the first harvest of the irrigated revealed that amaranth had higher values for all organs except the leaves while the non-irrigated showed that quinoa had higher values than amaranth in all organs but the seeds.

The second harvest of the irrigated treatment revealed that amaranth had slightly higher values for the branches while quinoa had the higher ones for the leaves, and the non-irrigated on the other hand showed that quinoa had the higher value in all the organs, but the seeds.

Mn

Comparison between species in 1992 for the irrigated treatments of the first harvest showed that quinoa had the higher value in all the organs except, in the stems, while the non-irrigated revealed that amaranth had the higher value for the branches but quinoa again had the higher values for the remaining organs. The irrigated treatment of the second harvest revealed that amaranth had the higher value for the branches but quinoa had the higher ones for the other organs. The same was observed for the irrigated treatment.

In (table 14) between soil moisture treatments comparison in the first harvest revealed that the non-irrigated had the higher values in all organs but the stems, while the second harvest showed that the non-irrigated had the higher values for the branches and leaves but the irrigated treatment had a slightly higher one for the seeds.

(table 15) showed that between soil moisture treatmentss showed that the non-irrigated had higher values in all but the seeds for the first harvest while the second harvest revealed that the irrigated had the higher ones in all but the leaves.

In 1993 comparison between the species for the first harvest of the irrigated treatment revealed that quinoa had higher values in the branches and the leaves while amaranth had higher ones for the seeds and the stems. The non-irrigated revealed higher values for quinoa for all the organs. The second harvest revealed that quinoa had higher values for all but the stems of the irrigated while it had the higher for all of the non-irrigated treatments.

Comparison between soil moisture treatmentss in the first harvest, (table 16), revealed that the irrigated treatment had the higher values for all the organs, while the non-irrigated had higher value for the leaves in the second harvest but the irrigated had higher ones for the branches and the seeds.

In (table 17) between soil moisture treatmentss comparison showed that in the first harvest the non-irrigated treatment had the higher values in all the organs. The same was also observed for the second harvest.

Fe

In 1992 between species comparison for the first harvest of the irrigated treatment showed amaranth to be higher in values for all the organs except the seeds while the non-irrigated showed that amaranth had the higher value for the branches and the leaves but quinoa had the higher ones for the seeds and stems.

In the second harvest of the irrigated, amaranth had the higher values for the leaves and branches while quinoa had the higher values for the seeds. In the non-irrigated for the second harvest amaranth had the higher values of branches and the leaves while quinoa had higher ones for the stems.

In (table 14) between soil moisture comparison showed that the non-irrigated had higher values in the branches and leaves while the irrigated had the higher value for the stems of the first harvest. The second harvest showed that the non-irrigated had the higher value for all the organs except the branches.

In (table 15) comparison between soil moisture combination for the first harvest showed that the irrigated had the higher values for the branches and leaves while the non-irrigated had the higher ones for the seeds and stems. The second harvest showed that the irrigated had the higher values for all the organs but leaves.

In 1993 between species comparison revealed that in the first harvest of the irrigated treatment amaranth had the higher values for the seeds and stems, while quinoa had the higher values for the branches and the leaves. In the non-irrigated amaranth had the higher values in all the organs.

In the second harvest of the irrigated treatment amaranth had the higher values for all the organs except the branches, but the non-irrigated showed that amaranth had higher values for all the organs.

In (table 16) between soil moisture comparison showed that the non-irrigated had higher values for the seeds and stems while the irrigated had higher ones for the leaves and branches. The second harvest revealed that the non-irrigated had higher values for the branches and leaves while the non-irrigated had higher values for the stems.

In (table 17) the first harvest showed higher irrigated values for all the organs while the second showed higher values for the irrigated treatment for the branches and seeds but the non-irrigated had the higher value for the leaves..

Between cropping seasons, differences were also observed. They were clearly manifested in Phosphorous with the 1993 cropping season having the higher values. It was the wetter of the two seasons.

4 DISCUSSION

The seed yields obtained in the field experiments were in the range of 242.5-540.0 g m-2 and may be classified as rather high ones (Roszewski 1995). Comparing seed yields it can be seen that: a) both irrigated and non-irrigated quinoa and amaranth did not respond substantially during 1992; b) non-irrigated quinoa did not show differences in yield between 1992 and 1993, c) in 1993 irrigated quinoa yielded twice as much as in 1992, and d) in 1993 both amaranth yielded less than in 1992. Therefore, causes of such differences in yielding could not be only attributed to the effect of experimentally simulated drought but involved its interactions with the time course of the weather during the whole cropping seasons as well (1992 dry and 1993 rainy ones).

Seed yields of quinoa might have been affected by the unfavorable daily average temperatures of 25oC, very often exceeding 35oC, reached in the very hot summer of 1992, because optimal temperature for the crop is about 15-20oC as is prevailent in Altiplano plateau in the Andes in the vicinity of the Titicaca Lake, 3700 m over sea level with maximum temperature of 23oC (Vacher, personal communication). It is why, even irrigation did not overcome the negative effect exerted by elevated temperatures on this temperate crop yielding. Amaranth is a warm climate plant (Kigel 1994) and it is cultivated in very hot regions such as Sierra Leone (Sesay 1991), so in 1992 in Poland (hot season) it yielded enormously well.

The final seed yields of both studied crops in 1992 and 1993 were results of their harvest index (HI) combined with total biomass production. Especially interesting was the HI for the non-irrigated amaranth in 1992, 0.36, which was extremely high compared with the irrigated one, 0.19. The non-irrigated HI for 1992 was equally high relative to the non-irrigated and irrigated ones in 1993 (0.19 and 0.16, respectively). Different HIs of amaranth in both studied combinations in 1992, did not reflect same in seed yields although dry matter of the whole in the high soil moisture plants was twice that in the low soil water content. Also HI of quinoa was higher for non-irrigated than irrigated plants in 1992, 0.20 versus 0.16. However quinoa yields were similar then. In 1993 HI for quinoa was lower for non-irrigated (0.13) than for irrigated ones (0.16). Thus, under unfavorable climatic conditions of 1992 total dry matter of both species was reduced but final seed yield was not changed. Higher HIs got in 1992 for non-irrigated studied crops could be the outcome of not only water shortage, but may also be due to higher temperature, on average an increase from 20oC by 5oC, after July, 15th. It might also be due to the negative effects of nitrogen fertilization at elongation stage when there was not enough soil water for its uptake and use.

In 1993 HIs of both crops, independent of irrigation, were in the range 0.13-0.19 and observed differences in final seed yields were caused mainly by differences in their biomass production. Quinoa, being a C3 plant with relatively lesser WUE, benefited much more under the rainy season of 1993 and irrigation than amaranth (C4 plant) (Edwards and Walker 1983). Despite higher soil moisture in 1993 than in 1992, seed yields of amaranth were lower in 1993 than in 1992. This could have been the result of poor conditions of low temperature for seed formation at the end of growth. Therefore, the HI results of amaranth for both combinations and cropping seasons showed that although increases in the vegetative or biological yield were realized due to irrigation, the economic yield if in the form of the seeds, did not respond to watering at all. The same result was obtained in the 1992 pot experiment. Plant adaptation to water shortage depends not only on photosynthetic pathway, but also osmotic adjustment, root development, etc. (Kigel 1994) The benefits of irrigation may be realized if plantations are grown for forage in both species.

Higher HIs of the non-irrigated than the irrigated plants seem to be of emence agronomic importance, both in terms of economic yield as well as during harvest. Size of A. cruentus shoots led to unnecessary combined harvesting problems using a cereal combine harvester. Massive size and stiffness of the shoots of amaranth interferred with the normal movement of the rotor (Chlebowski 1994). The moisture content in amaranth is usually high at harvest, unlike in true cereals. The high moisture dampened the seeds markedly causing post-harvest problems. Hence, the lesser the size of the stem due to non-irrigation, the better.

The Yield of both pseudocereals, as in other plant species, was a product of many physiological processes such as photosynthesis, respiration and assimilate distribution, which are in turn modified by such factors as soil water content, irradiance, soil and air temperatures, photoperiodicity etc. (Maleszewski et al. 1993, Loboda 1994). On the basis of the performed measurements the correlation coefficients between various gas exchange parameters were calculated for both plot and pot experiments. Noteworthy is that the correlation between photosynthesis and stomatal conductance was found, although the extent of the significance of the correlation was somehow variable. In quinoa (C3 plant), especially under the high soil moisture, these two prameters were found to be correlated (r= 0.89-0.90), while for amaranth (C4 plant) no significant correlation was found between the same attributes for the high soil moisture level. Photosynthesis and intercellullar CO2 (Cint) were usually not correlated. As significant differences existed between species in the intercellullar concentration of CO2 with quinoa comparing favourably to amaranth, it is rather plausible to state that this is related to the different carboxylation pathways (Ehleringer and Monson 1993).

The specific significant differences between species and soil moisture treatments in the plot and in the pot experiments of 1992 and 1993 in stomatal conductance may be connected with the fact that amaranth has an effective mechanism of trapping CO2 from the various metabolic processes reuse it, preventing it from escaping out through the stomata (Edwards and Walker 1983, Sestak 1985). In this way, the C4 plants are able to open their stomata economically, in so far as minimizing transpiration, unlike C3 plants (Bethenod et al. 1996).

Some studies are of the conclusion that partial closure may be generally beneficial for plants (Waggoner and Zelitch 1965; Shimshi 1963, Raschke 1976), however, photosynthetic rate is proportional to stomatal conductance (Farquhar and Sharkey 1982, Mansfield et al. 1990). Indeed, the 1992 plot plants of quinoa showed that the plants with imposed water shortage had lower stomatal conductance than the unstressed ones. More drought resistance varieties of herbaceous and even tree mesophytes show a greater degree of stomatal closure than the less resistant varieties of oats (Stocker 1956), peanuts (Gautreau 1970), sorghum (Henzell et al. 1975, 1976) and red maple (Townsend and Roberts 1973).

The obtained higher WUE for amaranth (C4) than for quinoa (C3) was in agreement with data of Ehleringer and Monson (1993). In both 1992 and 1993, higher WUE observed for non-irrigated plants of both studied species was mainly a result of their lower photosynthesis and transpiration.

Transpiration and intercellular CO2 were found to have no correlation in all experiments, while transpiration and stomatal conductance were found to do so only in 1993 (r=0.89-0.94). There is increasing evidence that plants detect conditions in the soil directly and respond accordingly to deteriorating conditions well before their roots lose the ability to extract water fast enough for their needs (Blackman and Davies 1985, Pasioura 1988a, Saab and Sharp 1989, Blum et al. 1991, Davies and Zhang 1991, Gowing et al. 1991). The roots send inhibitory signals to the leaves that may slow leaf expansion and close stomata well before any fall in water status is evident in the shoot. When they do so they are in effect displaying a feed forward response. The hormones such as abscisic acid (ABA) implicated in the feedfoward response are carried in the transpiration pool. Tardieu et al. (1992 b) suggested a definite correlation between xylem ABA and stomatal conductance. Tardieu et al. (1992 a) and Wartinger et al. (1990) reported that increases of xylem ABA of less than 200 (mol m-3 for plants in the field may lead to 90% reduction in stomatal conductance. Furthermore even if we consider the findings of Tardieu et al. (1992 b) leaf water potential (Vacher 1996) is as important as ABA in stomatal conductance and in this way in transpiration. ABA is synthesized by dehydrating roots (Cornish and Zeevart 1985; Watton et al. 1976) in non-growing tissues as well as in apices, and in the cortex as in the stele (Harting and Davies 1991).

The assimilated during photosynthesis CO2 undergoes distribution within plants so to evaluate seed yielding potential and study transport of carbon to forming seeds (Nalborczyk et al. 1981) radiolabelling was used at flowering stage.

The trend of significant specific differences, indeed in some organs even highly significant, in both the low and high soil moisture combinations was found to be the same.Higher values observed in the top, middle and bottom leaves of both amaranth treatments and higher values in the flowers and the branches of quinoa in the radioactivity may be due to quinoa flowers been stronger acceptors hence they had priority in the allocation of photoassimilates (Huber 1983).

Quinoa compared favorably to amaranth in the radioactivity of the branches as amaranth does not put a premium in the development of branches. The contribution of the branches in the total plant weight is small in amaranth (Chwedorzewska and Nalborczyk 1994) compared with quinoa. During the first harvest of amaranth low soil moisture combination revealed the readily-noticeable early development of branches. Indeed, drought led to early appearance of branches probably as a means of preserving resources (Chwedorzewska and Nalborczyk 1994).

The finding the low soil moisture combination displayed the higher radioactivity with respect to the bottom leaves in amaranth during the first harvest may be connected with the allocation of photoassimilates from the branches, to which they are closest. Indeed, Huber (1983) stated that sinks seem to be supplied largely from source leaves near to them. The low soil moisture compared favourably to the high soil moisture combination in the petioles what may be due to the fact that turgor in the phloem of the petioles of the high soil moisture combination enhanced speedy flux translocation (Farrar and Minchin 1991).

The low soil moisture compared favourably to the high soil moisture combination in the top leaves, which were not mature enough during the first harvest to optimize photosynthesis it may be due to import of assimilates to enhance growth and metabolism (Farrar and Minchin 1991). It is likely that the top leaves, of the low soil moisture combination were initially sinks.

During the second harvest, amaranth again displayed higher values in most organs except the branches. The changes of the distribution pattern of the two species during this harvest were characteristically different. In amaranth the flowers, stems and the petioles gained at the expense of the branches, top, middle and bottom leaves and specific distribution pattern was conserved in both the high and low soil moisture combinations, by giving priority to the flowers and stem (Wallop 1995). In quinoa conservation of a specific distribution pattern was not observed. The flowers gained considering their strategic position to the top, bottom and middle leaves. In the low soil moisture however, the bottom leaves were noted to have gained. The distribution pattern may have been influenced by sink strength rather than distance from source (Geiger et al 1985; Huber 1983; Starck and Ubysz 1974).

In accordance with the time course of the growth indices (Cartujano et al. 1985, Chwedorzewska 1994) during both cropping seasons, for the two species in both combinations, three developmental phases were identified. Phase “A” characterized early development, phase “B” concerned secondary development, in preparation for the third and final phase “C” describing the generative phase. Obviously the beginning or end of those phases sometimes differ due to either specific or climatic reasons. The three phases of growth and development were more accentuated in 1993 than in 1992 in both combinations and species.

The increase in ASI and LAI in phase “A” of both combinations of A. cruentus in 1992 signified a high percentage contribution of the assimilatory surface during the first part of the phase. Notwithstanding the huge contribution of the assimilatory surface area at the begining of the phase, RGR and CGR did not respond favourably to irrigation. The reason may be that most of the leaves present were too young and could not yet reach high net photosynthesis (Sestak 1985). This is substantiated by the reduced ULR. The differences in CGR between combinations in the beginning might have been reflected in the SLA. The differences in thickness may be due to that the irrigated plants had more biomass which enabled them, in turn, produce more, leading to increased growth.

The dynamics of biomass accumulation as well the values of LAI and LAD during the phase “B” markedly showed that the canopy was closing up. The assimilatory surface could not fetch optimum increase in biomass. The moisture condition during this phase was sub-optimal as indicated by much lower than 1 hydrothermal index. This may have caused the reduced efficiency of the assimilatory apparatus (Cartujano et al.1985, 1987).

The reduction in the size of the assimilatory apparatus, in both combinations during phase “C”was substantiated by the percentage contribution. The initial rise of SLA may be associated with the increased contribution of young thinner leaves to LWR and LAR, which continued to decrease. The late development of the assimilatory apparatus in the non-irrigated combination was reflected by the rise in ULR, except for the brief fall during the period between 79 and 91 DAE.

In phase “A”, in 1993 A. cruentus developed a huge assimilatory apparatus. but the difference between combinations was almost unnoticeable.The initial robustness in growth and development of the assimilatory apparatus was reflected in its elevated ULR, CGR and RGR. Both CGR and ULR were noted to end up with a significant rise at the end of the phase. Same RGR ended rising in both combinations by then. The SLA fell steeply during the phase, indicating the rate at which the thickening was taking place. Later, as is mostly the case (Evans 1972, Hunt 1982, Lambers and Poorter 1992), it did not change very much throughout the cropping season.

The second phase (“B”) coincided with the production of the branches. The phase revealed a reduction in the percentage contribution of the assimilatory apparatus. The RGR ended markedly lower than it started at the end of this phase, although ULR increased. The decrease of the photosynthesizing to the non-photosynthesizing parts of the plant through the developmental phases in terms of LWR and LAR kept falling leads to a reduction in RGR (Cartujano et al.1985, 1987).

The CGR also revealed little response to ontogeny by the end of the phase. This may be due to the fact that ULRc and LAI were also less responsive. Both indices are related to CGR by way of the following relationship: CGR = ULRc x LAI (Watson 1947, Nichiporovich 1967, 1968, Ustenko and Yagnova 1967, Wassink 1968, Pietkiewicz 1985). The ULRc did not differ from the indices of the individual plants. Some important factors of net photosynthetic production are the size of the assimilatory organ and leaf arrangement. These factors may lead to mutual shading and thus reduce ULRc as against that of single leaf (Stoy 1965).The lack of marked differences in the progress of both ULRc during both cropping seasons, 1992 and 1993, might be due to the fact that the size of the assimilatory apparatus caused the closure of the canopies. This may have been more beneficial than the negative effects of mutual shading especially in the area of reducing the temperature of the soil below the canopy which, in turn, indirectly promotes net photosynthesis (Watson 1952).

The third phase (“C”) revealed further reduction in the percentage contribution of the assimilatory apparatus and LWR and LAR reflected the reduced percentage contribution of leafage.The LAI was the only one describing green parts of plants in the non-irrigated combination which did not depict the reduced assimilatory surface during the phase. The CGR which was equally less responsive to ontogeny than RGR and ULR reached its peak in both combinations during this phase and it looked like CGR took more after LAI than ULR in the equation expressing CGR.

Indeed, Watson (1947, 1952, 1958) stated that in most stands a knowledge of the changes in LAI is the key to understanding the changes in other growth characteristics especially ULR, which in this case displayed inverse relationship as suggested by Stoy (1965). Duration of time over which the plant maintains its active assimilatory apparatus in terms of LAD as integral of LAI is very important as it is sometimes used to estimate ULRc by dividing the maximum attained weight by the over time integral of the crop assimilatory surface Ac (Nichiporovich et al. 1961; Kvet 1962; Stoy 1965) or since it used to be highly correlated with the yield more than any other characteristic (Birke 1965).

As in 1992 in C. quinoa the dynamics of biomass accumulation in phase “A” rose steeply it probably intuitively reflected good progress in early crop establishment. In phase “B” it was revealed a reduction in the percentage contribution of the leaves in both combinations while the branches increased their contribution in the irrigated but somewhat reduced their contribution in the non-irrigated treatment. The dynamics of biomass accumulation in the phase means the plants were using their huge assimilatory surface from the first phase to add to their biomass. The irrigated combination had lesser gradient, with smaller dynamism and the SLA revealed differences between the combinations. The LAI increased in both combinations, leading to closing up of canopies

The third phase (“C”) revealed a clear reduction in the percentage contribution of the assimilatory apparatus. The dynamics of biomass accumulation increased in the irrigated combination and fell in the non-irrigated, at the beginning of the phase. The CGR also showed differences though in both combinations a fall was recorded. The fall both of CGR and RGR may be due to the increase in the contribution of the non-assimilatory organs, such as the inflorescence to the plants DM.

The 1993 C. quinoa phases were also similar to the three earlier-mentioned ones. Phase “A “also revealed significant gains in assimilatory apparatus. The ULR values in both the canopy and the single plant slightly differed between combinations. The non-irrigated plants reached its highest value at the end of this phase while the irrigated ones reached by then its least value. The irrigated had already started to show signs of the inverse relationship between ULR and LAI even at the end of the preliminary phase. In phase “B”, the assimilatory apparatus increased considerably, especially in the irrigated combination where the LWR was rising from a local minimum. The dynamics of biomass accumulation in both combinations showed considerable gain. In phase “C” the gain in the assimilatory surface was clearly reflected by the dynamics of biomass accumulation curve.

If one reconsiders the growth of amaranth and quinoa in view of dry matter contribution of principal organs then it noteworthy that during the hot summer 1992 there were lesser leaves especially in the non-irrigated combinations than in 1993, and less petiols especially for nonirrigated amaranth in 1992. Also under low soil water content and high temperature (1992) there were less branches than in 1993. The percentage of the main inflorescences under all treatment of amaranth was much higher than in 1993, while quinoa developped that year earlier auxillary ones.

Higher nitrogen (crude protein) content in the leaves of quinoa than in amaranth reflects differences in their photosynthetic pathway, mainly its allocation to rubisco which is the principal N-compound in the leaves and there is more of this enzyme in C4 than C3 plant (Sage and Pearcy 1987, Kigel 1994). Amount of nitrogen could influence stomatal conductance of irrigated and non-irrigated plants because the decreasing nitrogen per leaf area caused lower stomatal conductance (Hunt et al. 1985).

Taking into account the same yields in both amaranth combination in 1992 but much lower ASI and much higher HI in non-irrigated combination than in irrigated one, it is tempted to speculate that in the former ones a significant amount of organic compounds, including N-containing compounds, needed for seed formation was stored in vegetative parts of the plants and remobilized later on.

The absence of any measurable defficiency syndrome clearly shows the efficiency of both alternative crops in the management of the nutrients. Even the low moisture treatment which cause reduced levels of the micronutrient did not show any syndromes. Uptake of the nutrient by both crops was similar. It was noted that results reached in this experiment were largely comparable to those of Bressani (1988), Saunders and Becker (1983) and De Bruin (1964).

CONCLUSIONS

1. Water shortage influences both biomass production and harvest index (HI) by decreasing and increasing respectively for A. cruentus (C4 plant) and C. quinoa (C3 plant).The situation was accentuate by the hotter season of 1992.

2. Under hot and dry season conditions, amaranth yields were much higher than quinoa independent of ample soil moisture conditions or not, while under rainy and cooler season seed yield of the latter species benefits much more.

3. WUE of amaranth is higher than that of quinoa and under water shortage changes proportionally for both species due to substantial reduction of photosynthesis and this drop is higher in amaranth than quinoa.

4. Reduced soil moisture results in higher allocation of photosynthate towards inflorescences and seeds of amaranth than in quinoa.

5. Drought negatively affects RGR mainly by lowering ULR whereas the LWR is not changed but SLA increases.

6. Under low soil moisture CGR of both crops decreases due to simultaneous diminishing of LAI and ULRc but the pattern of the latter is inherent in CGR changes.

7. Under weather conditions similar to those in 1992 and 1993 water shortage does not severely affect mineral relations of A. cruentus and C. quinoa.

BIBLIOGRAPHY

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TABLE 13: FERTILIZER APPLICATION IN POTTED EXPTS.

|TIME OF APPLN. |MACROELEMENTS |MICROELEMENTS |

|BEFORE SOWING | Fertilizer |Amt./pot |Amt. of H2O/pot | Fertilizer |Amt./pot |

| | |(g) |(ml) *** | |(mg) |

| |KNO3 |2.16 |20 |H3BO3 |5 |

| |NH4NO3 |2.00 | 20 |MnSO4 |5 |

| |K2SO4 |0.74 | 20 |ZnSO4 |0.2 |

| |MgSO4.7H2O |0.65 | 20 |CuSO4 |0.2 |

| |KH2PO4 |0.575 |10 |NH4 - Molybdate |0.5 |

| |Ca(H2PO4)2.H2O |0.89 |Dry |Fe-citrate |0.1 |

| | | | |(1%) | |

|EARLY FLOWER BUD |NH4NO3 |4.57 |20 |Fe-citrate |0.1 |

|STAGE | | | |(1%) only | |

| | | | |C. quinoa | |

|FULL FLOWERIG |NH4NO3 (only MT-3) |4.57 |20 |none |none |

|STAGE | | | | | |

*** Amount of water per pot needed to dissolve or disperse fertilizer.

APPENDIX 1

Below are two pictures from the 1992 potted experiment. Top picture shows amaranth and quinoa at the intensive growth stage while the bottom picture shows a closer view of quinoa at this same stage.

APPENDIX 2

Below are pictures from the 1992 potted experiment. The top picture shows amaranth and quinoa. Early maturing quinoa was already at the stage of final harvest while amaranth was not. The bottom picture shows amaranth at the stage of final harvest.

APPENDIX 3

Immidiately below our background shows irrigated amaranth (left) and quinoa (right) in the early flowering stage while the bottom picture shows irrigated amaranth and quinoa (far right) in the mid flowering stage from the 1992 plotted experiment.

APPENDIX 4

Top picture shows irrigated amaranth at full flowering while bottom largely shows irrigated quinoa (1992).

APPENDIX 5

Top picture shows non-irrigated amaranth and quinoa at mid flowering, while bottom shows the same species at full flowering stage (1992).

APPENDIX 6

Top picture shows irrigated amaranth and quinoa at the flower bud stage while bottom picture shows non-irrigated amaranth (foreground) and quinoa (background).

APPENDIX 7

Top picture measurement with the Li-6200 gaseous exchange equipement while bottom shows amaranth and quinoa before final harvest (1993 expt.).

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