Prota 2: Vegetables/Légumes
Sp. pl. 2: 991 (1753).
2n = 32, 34
Amaranthus hybridus auct. non L.
Prince’s feather, amaranth (En). Amarante, brède malabar (Fr). Amaranto, bredo (Po). Mchicha (Sw).
Origin and geographic distribution
Amaranthus hypochondriacus originates from North America, possibly as a hybrid between the north American wild Amaranthus powellii S.Wats. and the cultivated Amaranthus cruentus L. Amaranthus hypochondriacus is now widely cultivated worldwide, in tropical, subtropical and temperate climates, but mainly as a grain and ornamental crop. It is also found in tropical Africa (e.g. Kenya), but its exact distribution is unknown because of confusion with related species.
Amaranthus hypochondriacus leaves are occasionally used as a potherb and the seeds are used as a grain. Its use as a grain crop is most important in Central and South America and in Asia. The seeds are used like maize: popped, roasted or milled. In Mexico the product is known as ‘zoale’ paste and ‘alegría’ cake and confections. In the Himalayas bread made from the seeds is very popular and the popularity of Amaranthus hypochondriacus as a grain crop in India is increasing. In Africa it is experimentally tried as a leafy vegetable. Amaranthus hypochondriacus is also grown as an ornamental.
Amaranth leaves contain per 100 g edible portion: water 84.0 g, energy 176 kJ (42 kcal), protein 4.6 g, fat 0.2 g, carbohydrate 8.3 g, fibre 1.8 g, Ca 410 mg, P 103 mg, Fe 8.9 mg, β-carotene 5716 μg, thiamin 0.05 mg, riboflavin 0.42 mg, niacin 1.2 mg, ascorbic acid 64 mg. The composition of the seeds of grain amaranth per 100 g edible portion is: water 12.7 g, energy 1495 kJ (356 kcal), protein 14.0 g, fat 6.0 g, carbohydrate 63.1 g, fibre 9.4 g, Ca 490 mg, P 455 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968).
In Western countries amaranth seed is recommended as a health food. The protein is characterized by the high lysine content (3.2–18%). The oil has antioxidant properties. The starch consists mainly of amylopectin; the very small starch granules make grain amaranth an attractive raw material for industrial uses. The significant amount of squalene (4–11% of the oil portion) means that grain amaranth may find a market niche for industrial production of products such as lubricants in the computer industry and in cosmetics and health foods.
Annual herb, erect or less commonly ascending, up to 2 m tall, often reddish tinted throughout; stem stout, branched, angular, glabrous or sparsely to moderately densely furnished with multicellular hairs. Leaves arranged spirally, simple, without stipules, long-petiolate; blade broadly lanceolate to rhombic-ovate, 2–18 cm × 2–15 cm, attenuate or shortly cuneate at base, obtuse to subacute at apex, mucronate, entire, glabrous to sparsely pilose, pinnately veined. Inflorescence stiff with thick branches, large and complex, consisting of numerous agglomerated cymes arranged in axillary and terminal spikes, the terminal one up to 45 cm long, usually with many lateral, perpendicular, thin branches. Flowers unisexual, subsessile; bracteoles 3–5 mm long and always longer than the tepals; tepals 5, lanceolate, 1–2 mm long with one equal to or longer than the fruit, the other 4 shorter; male flowers with 5 stamens c. 1 mm long; female flowers with superior, 1-celled ovary crowned by 3 thick, spreading stigma branches about 1.7 mm long. Fruit an obovoid to rhombic capsule 1.5–2 mm long, circumscissile, with a short beak, 1-seeded. Seed obovoid to ellipsoid, compressed, c. 1 mm long, whitish to yellowish or blackish. Seedling with epigeal germination; hypocotyl 10–12 mm long; cotyledons about 18 mm × 5 mm, fleshy, petiolate.
Amaranthus comprises about 70 species, of which about 40 are native to the Americas. It includes at least 17 species with edible leaves and 3 grain amaranths. Amaranthus hypochondriacus belongs to both categories. Amaranthus hypochondriacus is part of the so-called Amaranthus hybridus complex, a group of species in which taxonomic problems are far from clarified because of apparently common hybridization and nomenclatural disorder caused by misapplication of names. Several cultivars of Amaranthus hypochondriacus exist; most of these have pale seeds, but some have black seeds.
Amaranthus hypochondriacus as a vegetable amaranth grows well at day temperatures above 25°C and night temperatures not lower than 15°C, but it is grown as a grain crop up to 2000 m altitude in the Himalayas. Shade is disadvantageous except in cases of drought. Amaranth is a quantitative short-day plant, which is an advantage in the subtropics, where the conversion to the generative stage is retarded during summer. Amaranths like fertile, well-drained soils with a loose structure. The mineral uptake is very high. Although Amaranthus hypochondriacus is fairly tolerant of adverse climate and soil conditions, escapes growing as a weed tend to disappear because they cannot compete with true weeds like Amaranthus spinosus L. or Amaranthus hybridus L.
Commercially vegetable amaranth is usually grown as a sole crop on beds. It is also found in intercropping systems with food crops and in home gardens. There are 2500–3500 seeds/g. The common cultivation practice is sowing in a nursery at a seed rate of 3–10 g/m2 and transplanting after 2–3 weeks. Wet rot or stemrot caused by the fungus Choanephora cucurbitarum is the main disease. It is favoured by wet conditions, low soil fertility and high nitrogen doses. Insects are a serious problem for amaranth growers. Caterpillars (Spodoptera litura, Helicoverpa armigera,Hymenia recurvalis) and sometimes grasshoppers are the most harmful. Most commercial amaranth growers harvest whole plants by uprooting 20–30 days after transplanting. Good growers normally harvest 20–25 t/ha (maximum 30 t/ha) of an uprooted crop (dry matter content 16%, edible portion 35–50%, being the total of leaves and young stems). The harvested plants are bundled, the roots are washed and the produce is packed for transport to the market. In markets and shops it is sprinkled with water to keep a fresh appearance. If uprooted, the vegetable can be kept fresh for some days by putting it in a basin with the roots in the water. It is sold in bunches or by weight.
Genetic resources and breeding
A collection of amaranths is kept at the Rodale Organic Gardening and Farming Research Center (OGFRC) at Kutztown, Pennsylvania, United States; South-East Asian accessions are kept at the Asian Vegetable Research and Development Center (AVRDC) at Tainan, Taiwan. African cultivars and introductions from OGFRC are kept at the National Horticultural Research Institute (NHR) in Nigeria and African cultivars at the AVRDC centre at Arusha, Tanzania. Indian collections are maintained at the National Bureau of Plant Genetic Resources (NBPGR) in New Delhi, India. Many national institutes have small working collections of local cultivars. Evaluation and variability studies are needed to reveal the amount of exploitable genetic variation. Breeding of Amaranthus hypochondriacus as a leafy vegetable does not occur; all efforts are directed toward development of good seed cultivars.
Amaranthus hypochondriacus is only occasionally used as a vegetable – its major importance, at least in America and Asia, will remain its use as a seed crop. To finally settle the name confusion, more research is needed to unravel completely the taxonomic and relational problems of the Amaranthus hybridus complex. This will also elucidate the distribution and importance of Amaranthus hypochondriacus in Africa, which are unclear at the moment.
• Costea, M. & Sanders, A., 2001. Preliminary results toward a revision of the Amaranthus hybridus species complex (Amaranthaceae). Sida, Contributions to Botany 19(4): 931–974.
• Grubben, G.J.H., 1993. Amaranthus L. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 82–86.
• Jain, S.K. & Sutarno, H., 1996. Amaranthus L. (grain amaranth). In: Grubben, G.J.H. & Partohardjono, S. (Editors). Plant Resources of South-East Asia No 10. Cereals. Backhuys Publishers, Leiden, Netherlands. pp. 75–79.
• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.
• Leung, W.-T.W., Butrum, R.R. & Chang, F.H., 1972. Food composition table for use in East Asia. Department of Health, Education and Welfare, Bethesda, United States. 334 pp.
• Sauer, J.D., 1967. The grain amaranths and their relatives: a revised taxonomic and geographic survey. Annals of the Missouri Botanical Garden 54: 103–137.
• Townsend, C.C., 1985. Amaranthaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 136 pp.
Correct citation of this article:
Jansen, P.C.M., 2004. Amaranthus hypochondriacus L. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.