Mucuna pruriens (L.) DC. cv. group Utilis
Mucuna pruriens: Prodr. 2: 405 (1825); cv. group Utilis: Westphal, Pulses in Ethiopia, their taxonomy and agricultural significance: 121 (1974).


2n = 20, 22, 24

Synonyms Mucuna utilis Wall. ex Wight (1840), Mucuna pruriens (L.) DC. var. utilis (Wall. ex Wight) Baker ex Burck (1893), Mucuna pruriens (L.) DC. f. utilis (Wall. ex Wight) Backer (1963).

Vernacular names Velvet bean (En). Cowitch (Am). Pois mascate, pois velus (Fr). Indonesia: kara benguk (Javanese), kowas (Sundanese), kekara juleh (Moluccas). Malaysia: kacang babi, kekaras gatal. Philippines: sabawel. Cambodia: khnha. Laos: tam nh. Thailand: mamui (central). Vietnam: d[aaj]u m[ef]o r[uf]ng.

Origin and geographic distribution Velvet bean is probably a native of tropical South or South-East Asia, and has been widely distributed throughout the tropics. It was introduced into Florida in 1876, from where its range was extended into temperate and subtropical areas by breeding. In the south-eastern United States it used to be the most important cover crop grown in combination with maize in an area of about 1 000 000 ha around 1920. Later, soya bean and commercial fertilizers rapidly replaced it and it disappeared from agricultural statistics in 1965. As a cover crop, it is now most important in Australia, Hawaii, the Fiji Islands, Indonesia, Malaysia and the Philippines.

Uses Velvet bean is mainly grown as a cover crop and green manure and is one of the most suitable crops for reclaiming land infested with weeds, especially with Cynodon dactylon L., Cyperus rotundus L. and Imperata cylindrica (L.) Raeuschel. It is recommended for use in rotation with cotton in Brazil to limit Fusarium oxysporum and Meloidogyne incognita infestation. In Central America, it is widely grown either relay planted with maize or as a rainy season fallow crop in rotation with dry season maize. It was formerly an important cover crop in citrus and banana plantations. In Georgia and northern Florida and in Mauritius it is used as a forage and as a component in pastures. Boiled seeds of velvet bean are occasionally eaten as a pulse. In Java the seeds are fermented and flattened into a kind of cake ('tempe benguk'), while immature pods and young leaves are sometimes boiled as vegetables. In the southern United States it is often grown as an ornamental.|In traditional medicine the pod hairs mixed with syrup, molasses or honey are taken as an anthelminthic, but the effect seems to be only minor. Ethanol extracts of the pod-hairs and leaves have an analgesic and anti- inflammatory effect in rats. The amino acid L-dopa used in the symptomatic relief of Parkinson's disease is extracted from the seed. Starch from the seed has been tested in Brazil in the preparation of food thickeners and adhesives.

Production and international trade Annual world seed production has been estimated to be 900 000 t. There is local trade in seed for consumption and in pod hairs. In Java, seed is currently (1996) sold at about US$ 1.00 per kg. No statistics are available on trade and production of seed for manufacturing L-dopa.

Properties Analysis of the aboveground organic matter indicates the following composition per 100 g dry matter: protein 15-24 g, ether extract 2 g, N-free extract 49 g, crude fibre 19 g, ash 15 g. Velvet bean plants decompose fairly rapidly, the rate may amount to 50% loss of dry weight in about 4 weeks.|Per 100 g dry matter seed contains: protein 23-33 g, crude fat 6 g, N-free extracts 52-57 g, fibre 7 g, ash 3.5 g, K 1.5 g, P 1 g, Ca 0.2 g, vitamin A 50 IU. The in vitro protein digestibility in cattle is about 72%. The nutritive value of the seed, either raw, boiled or roasted, is not very high, similar to e.g. Lima bean (Phaseolus lunatus L.), but better than sword bean (Canavalia ensiformis (L.) DC. When fed to pigs in large quantities, seed causes severe vomiting and diarrhoea, probably due to the presence of L-dopa. Two important non-protein amino acids are found in the seed and in smaller amounts in the stems and leaves: L-dopa (L-3.4- dihydroxyphenylalanine) from which dopamine, an important medicine to relieve the effects of Parkinson's disease, is prepared, and DMP (N- dimethyltryptamine) which has hallucinogenic properties. The L-dopa content varies from 1.6-3.3% and is sufficiently high for commercial extraction. The seed also contains a number of alkaloids, the most important of which being mucunaine, prurienine and serotine. The stinging hairs of velvet bean, used as an anthelmintic, contain a pruritogenic, proteolytic enzyme and granular matter, tannic acid and resin. The weight of the seed varies greatly between cultivars, and ranges from 550-850 g per 1000 seeds.

Description A vigorous, climbing, pubescent annual herb, 2-18 m long. Roots numerous, 7-10 m long, taproot with many laterals. Stem slender, terete, slightly pubescent with white, straight, short and long hairs, glabrescent. Leaves alternate, 3-foliolate; stipules caducous, subulate, about 0.5 cm long, white-hairy outside, glabrous inside; petiole (3-)4- 9(-13.5) cm long, slightly grooved above, generally slightly pubescent, pulvinus pubescent; rachis (0.5-)1-2 cm long, grooved above, slightly pubescent; stipels filiform; lateral leaflets conspicuously asymmetrical, obovate, rhombic, ovate or elliptical, (5-)7-15(-19) cm x (3-)5-12(-17) cm, terminal leaflet symmetrical and as a rule smaller, apex acute to acuminate-mucronate, base rounded, covered with appressed, grey or silvery hairs turning black when dry. Inflorescence an axillary raceme, up to 32 cm long, 1-many-flowered, silvery pubescent; rachis tubercled without lateral branchlets; bracts early caducous, narrowly triangular-elliptical, 5-10 mm long; pedicel 1.5-10 mm long, with 2 bracteoles 10 mm x 2 mm, near the base of the calyx; calyx campanulate, tube 4-7 mm long, 5-lobed, appressed silvery pubescent outside, glabrous inside, upper pair of lobes connate, the other 3 lobes subequal, triangular, 3-9 mm long, acute; corolla blackish-purple, pale lilac or white; petals clawed, auricled; standard hood-shaped, much shorter than other petals, 17-22 mm x 11-15 mm, fleshy especially towards the base, rounded at the top; wings narrowly obovate, 32-35 mm x 8-10 mm, fleshy especially towards the base, rounded at the top, finely and patently pubescent at base; keel about 35 mm x 5 mm, narrow in the middle, entirely split dorsally, ciliolate at the edges, glabrescent towards the top, ventrally split near the base and apex, apical part hard and ending in a horny tip; stamens 10, diadelphous. Fruit an oblong, (1-)3(-7)-seeded pod with oblique top, somewhat compressed laterally, slightly bulging over the seeds, 4-13 cm x 1-2 cm, finely pubescent with white to light brown hairs; valves thick and leathery, with prominent, complete rib and 2-3 partial, less prominent ribs. Seed oblong- ellipsoid, somewhat laterally compressed, about 15 mm x 10 mm x 5 mm, colour variable, light or pinkish-brown often with dark brown mosaic, mottled with grey, purple or black background, almost entirely black, grey, greyish-black or white; hilum oblong, lateral, eccentric, about 4 mm long, surrounded by a prominent, cream-coloured aril, with scale-like extension at the rim. Seedling with hypogeal germination.

Growth and development Young plants of velvet bean have a purplish, pubescent epicotyl; the first 2 leaves are opposite, simple, deeply cordate. They grow very fast and can cover the ground in 2-3 months, forming a thick even blanket about 60 cm deep, smothering most weeds. Its climbing habit further contributes to its capacity to suppress the growth of weeds. Distribution of the roots tends to be very shallow and concentrated in the fertile topsoil. Roots form where creeping stems touch the soil. Velvet bean forms root nodules with slow-growing Rhizobium and fixes atmospheric nitrogen. Flowering commences 90-145 days after sowing and pods begin to ripen 2-3 months after flowering. Self-pollination is the rule. The first harvest of dry seed may be expected after 200-230 days. Rapid growth declines in most cultivars at an age of 5 months when stems begin to dry and defoliate and roots begin to rot. Maximum survival is generally 8-10 months, but some velvet bean cultivars (Mauritius bean) may cover the ground for over 2 years.

Other botanical information Mucuna pruriens has often been classified in the genus Stizolobium P. Br., but at present Stizolobium is generally considered a subgenus or section of Mucuna Adans. Wild forms of Mucuna pruriens have pods covered with irritating bristly hairs which are absent, or nearly so, in cultivated forms. Several cultivated forms of Mucuna pruriens have been described as distinct species: Mucuna aterrima (Piper & Tracy) Merrill, Mauritius bean, grown as a cover crop and green manure in Australia, Brazil, Mauritius and the West Indies; Mucuna capitata (Roxb.) Wight & Arnott, cultivated in India and Indonesia for its seed; Mucuna deeringiana (Bort) Merrill, Florida or Georgia velvet bean, grown for fodder; Mucuna hassjoo (Piper & Tracy) Mansf. (synonym Stizolobium hassjoo (Sieb.) Piper and Tracy), Yokohama velvet bean, an early maturing type from Japan; Mucuna nivea Wight & Arnott (synonyms Mucuna lyonii Merrill and Mucuna cochinchinensis (Lour.) A. Chev.), Lyon bean, cultivated for the immature pods eaten as a vegetable in South-East Asia; Mucuna pachylobia (Piper & Tracy) Rock (synonym: Stizolobium pachylobium Piper & Tracy), cultivated in India as a green fruit vegetable; Mucuna utilis Wall. ex Wight, Bengal bean, cultivated in India and Mucuna velutina Hassk. All these species, mainly distinguished by the nature of their hairs and colour of flowers and seed are now considered cultivars of Mucuna pruriens cv. group Utilis. A clear classification of the different cultivars into cv. groups is badly needed.|Several cultivars differing in plant type and time to maturity have been released in the United States. The best known are: '120-Day Florida', a cultivar with medium-sized, mottled seed, usually requiring over 120 days to mature in the United States; 'Early Jumbo', a large-seeded cultivar maturing in about 175 days, easy to harvest for seed because the pods grow in clusters that can be picked together; 'Osceola', a white-flowered heavy seed producer with pods almost devoid of stinging hairs; 'Victor', maturing in about 190 days, producing about 1400 kg seed per ha.

Ecology Velvet bean tolerates a wide range of annual rainfall from 400-3000 mm, but is not drought resistant because of its shallow root system. Only Mauritius bean shows better drought tolerance. Velvet bean grows best at an average annual temperature of 19-27C. Plants are sensitive to frost and exposure to a temperature below 5C for more than 24 hours is fatal even for cultivars from Florida. A night temperature of over 21C is said to stimulate flowering. Velvet bean requires a high light intensity and yields poorly when intercropped with cassava or maize. It grows best on well-drained sand and clay soils and on ultisols with a pH of 5-6.5, but also grows vigorously on acidic sandy soils. It does not tolerate waterlogging. In soils with a fertile topsoil and an acidic subsoil, the latter being low in P and high in Al, root growth is concentrated in the topsoil. If a fertile topsoil is absent an extensive root system develops even in acidic soils.

Propagation and planting Propagation is mostly by seed. Seed requires no scarification, but dry seed requires soaking in water for 24 hours. The germination rate of fresh seed is 90-100%, declining with time. Seed stored in a cool dry place remained viable for about 2 years, but seed stored in a sealed jar for 3 months lost its viability. Germination takes 4-7 days. In South-East Asia, sowing is done from January to May, at the onset of the rainy season. Seed is placed 2 cm deep with 2-4 seeds per hole. For cover crops in rubber plantations in Indonesia and Malaysia, a spacing of 2 m x 1 m or 1.5 m x 1.5 m is recommended, requiring about 15 kg seed per ha. In sugar-cane plantations in Mauritius, a spacing of 60-100 cm x 60-100 cm is used. When planted as a green manure crop in Indonesia, it is sown at a spacing of 30 cm x 20-30 cm with 2 seeds per hole, while elsewhere it is also broadcast. When intercropped with maize in the United States, it is sown in rows 90-120 cm apart at a seed rate of 4-15 kg/ha.

Husbandry After sowing, velvet bean requires 1-2 weedings. Hand weeding is most common, but both pre- and post-emergence herbicides are applied effectively. When grown as a cover crop in tree plantations, velvet bean is mostly grown in combination with other cover crops, because of its short life span. Species commonly used in such combinations are Calopogonium mucunoides Desv. and Calopogonium caeruleum (Benth.) Sauv., Centrosema pubescens Benth. and Pueraria phaseoloides (Roxb.) Benth.|Velvet bean is currently being tested in a number of cropping systems, mainly in combination with maize. It is either intercropped, relay planted 15-40 days after sowing of the maize, or grown in rotation. When grown as a green manure crop, velvet bean tends to become weedy when the seed is left to mature. In tests in Nigeria, mowing velvet bean before maturation of the seed followed by zero tillage planting of maize effectively solved this problem.

Diseases and pests Velvet bean is little affected by diseases, although in Zimbabwe, it is very susceptible to a vine rot of unknown cause that can wipe out the crop. It is resistant but not immune to root-knot nematodes and is attacked by several other Meloidogyne spp. Very few insect and small mammals attack velvet bean possibly because of its high L-dopa content. The velvet bean caterpillar (Anticarsia gemmatalis) in Florida is one of the few insects reported to cause damage. In Malaysia, green bugs (Brachyplatys spp.) feed on the leaves. Striga gesnerioides (Willd.) Vatke parasitizes the velvet bean.

Harvesting The optimum time for harvesting velvet bean for green manure is at flower initiation, attained 55-145 days after sowing, depending on the cultivar. Plants are pulled up by hand or by hoe and buried in the soil. Grown for forage in the United States, it may be harvested 90-120 days after sowing, when the pods are still young. In Malaysia, the first harvest for fodder can take place 2 months after sowing. A cutting interval of 5 weeks and cutting at a height of 30 cm provide a reasonable yield of forage of adequate quality. Harvesting for pod production can start as soon as the pods start changing colour from green to dark brown or black; in Malaysia this is possible at 215-255 days after sowing. Pods are harvested by hand. When intercropped with maize, cutting velvet bean below the level of the maturing maize cobs facilitates harvesting the latter.

Yield On good soils in the southern United States, seed yields of 900- 1200 kg/ha and even of 1500 kg/ha in Hawaii have been obtained. In India, seed yields range from 250-1150 kg/ha. Green forage yields in the United States are 3-6 t/ha 90-120 days after sowing and 18 t/ha at the end of a growing season. When grown as a cover crop in rubber plantation a fresh organic matter yield of about 2 t/ha can be obtained in about 6 months.

Handling after harvest Green manure should be buried in the soil immediately after harvesting. If left to dry above the ground, the nitrogen content may be reduced by as much as 50%. Dried pods are threshed with a regular grain thresher or by hand. In Java and Africa, threshing is done by beating the pods put in sacks. Only the best seed is used to make 'tempe'. It is washed and boiled for 2-3 hours. After cooling, seeds are dehulled and soaked in ample water for 1-2 days, changing the water 2-3 times a day to ensure that all toxic substances have been removed. The cotyledons are then chopped into smaller pieces and steamed. When cool, the beans are sieved and inoculated evenly with the fungus Rhizopus arrhizus or Rhizopus oryzae, flattened and wrapped in banana leaves or a similar material for 24-40 hours at 31C. The product is a cake covered with mats of mycelium. It is consumed fried, or mixed with vegetables in a soup.

Genetic resources Natural populations of wild forms of Mucuna pruriens are no longer common in Indonesia, while other species of Mucuna, such as Mucuna acuminata R. Grah., Mucuna gigantea (Willd.) DC. and Mucuna macrophylla Miq. are also threatened. Hybridization of cultivated genotypes with these species may become important in breeding programmes. Germplasm collections of Mucuna spp. are maintained, for example at the Southern Regional Plant Introduction Station of the United States Department of Agriculture, Griffin, Georgia, which has 32 accessions of velvet bean.

Breeding A number of cultivars have been released in the United States, but no current programmes are known to exist.

Prospects Velvet bean covers the soil quickly, is very productive, resists most diseases and pests, and is adapted to a wide range of environmental conditions. It is one of the few cover crops and green manures that yield valuable byproducts, making it attractive to small-scale farmers. Its resistance to diseases and pests also make it an attractive vegetable and pulse crop. Its future importance as a source of L-dopa depends on the existence of alternative plant sources and methods of producing this compound synthetically.

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Author: N. Wulijarni-Soetjipto & R.F. Maligalig

Source of This Article:
Wulijarni-Soetjipto, N. & Maligalig, R.F., 1997. Mucuna pruriens (L.) DC. cv. group UtilisIn: Faridah Hanum, I & van der Maesen, L.J.G. (Editors). Plant Resources of South-East Asia No. 11: Auxiliary plants. Backhuys Publisher, Leiden, The Netherlands, pp. 199-203

Recommended Citation:
Wulijarni-Soetjipto, N. & Maligalig, R.F., 1997. Mucuna pruriens (L.) DC. cv. group Utilis[Internet] Record from Proseabase. Faridah Hanum, I & van der Maesen, L.J.G. (Editors).
PROSEA (Plant Resources of South-East Asia) Foundation, Bogor, Indonesia.
Accessed from Internet: 31-Oct-2020