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Vigna mungo (L.) Hepper

Protologue
Kew Bull. 11(1): 128 (1956).
Family
Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)
Chromosome number
2n = 22
Synonyms
Phaseolus mungo L. (1767).
Vernacular names
Black gram, urd bean, urad bean (En). Haricot urd, urd (Fr). Feijão urida (Po). Mchooko mweusi (Sw).
Origin and geographic distribution
Black gram was most probably domesticated in India from its wild ancestral type, which is also found in Bangladesh, Pakistan and Myanmar. At present black gram cultivation is of major importance in India only, but it is also grown to some extent throughout tropical Asia. In Africa it is grown in Gabon, DR Congo, Kenya, Uganda, Tanzania, Malawi, Mozambique, South Africa, Madagascar and Mauritius. It is grown in the United States and Australia mainly as a fodder crop.
Uses
Black gram seeds are eaten as a pulse, direct or in various preparations (whole or split, boiled or roasted, ground into flour for cake, bread or porridge). It is with the flour of black gram that in India the flat biscuits ‘papadum’ are made. Seed sprouts are also consumed. Green pods are eaten as a cooked vegetable. Small quantities of the pods and foliage are used to supplement cattle feed or as forage. Sometimes black gram is sown as a cover crop and for green manure. The pod walls are fed to cattle. Flour from the seed is used as a substitute for soap; it makes the skin soft and smooth. In traditional medicine, the seed is used for its suppurative, cooling and astringent properties, e.g. pounded and applied as a poultice on abscesses.
Production and international trade
In India, the major producer and consumer, average annual production of black gram seed is about 1.3 million t from 3 million ha. Thailand produces annually about 90,000 t which is mainly exported to Japan, where seed sprouts from black gram are preferred to those from green gram (Vigna radiata (L.) R.Wilczek) because of their longer shelf life. Annual production in Pakistan is about 28,000 t from 57,000 ha, and in Sri Lanka 6000 t from 8000 ha. Sri Lanka additionally imports 6000 t/year.
Properties
Black gram seeds contain per 100 g edible portion: water 8.6 g, energy 1470 kJ (351 kcal), protein 25.1 g, fat 1.8 g, carbohydrate 61.0 g, crude fibre 4.4 g, Ca 196 mg, Mg 260 mg, P 575 mg, Fe 6.8 mg, Zn 3.1 mg, vitamin A 114 IU, thiamin 0.36 mg, riboflavin 0.28 mg, niacin 1.8 mg, vitamin B6 0.28 mg, folate 628 μg and ascorbic acid 4.8 mg. The essential amino-acid composition of black gram seeds per g nitrogen is: tryptophan 65 mg, lysine 415 mg, methionine 91 mg, phenylalanine 365 mg, threonine 217 mg, valine 351 mg, leucine 518 mg and isoleucine 319 mg (Haytowitz & Matthews, 1986). Black gram seeds have shown anti-atherogenic activity in guinea pigs.
Botany
Erect, hairy annual herb up to 100 cm tall, sometimes twining, with a well-developed taproot; stem diffusely branched from the base, furrowed. Leaves alternate, 3-foliolate; stipules peltate, ovate; petiole 6–20 cm long; stipels falcate; leaflets ovate or rhombic-ovate, 4–10 cm × 2–7 cm, entire, acuminate. Inflorescence an axillary false raceme; peduncle up to 18 cm long. Flowers bisexual, papilionaceous, small; bracteoles linear to lanceolate, exceeding the calyx; calyx campanulate; corolla yellow, standard 12–16 mm wide, wings about as long as standard, keel spirally coiled with a terminal horn-like appendage; stamens 10, 9 united and 1 free; ovary superior, style spirally curved. Fruit a cylindrical pod 4–7 cm × 0.5 cm, erect or almost so, with long hairs and short hooked beak, 4–10-seeded. Seed ellipsoid, up to 5 mm long, with square ends, and raised and concave hilum, usually black or mottled, sometimes green. Seedling with epigeal germination.
Vigna comprises about 80 species and occurs throughout the tropics. Vigna mungo belongs to subgenus Ceratotropis, which also includes Vigna radiata (L.) R.Wilczek (mung bean), Vigna umbellata (Thunb.) Ohwi & H.Ohashi (rice bean), Vigna angularis (Willd.) Ohwi & H.Ohashi (adzuki bean) and Vigna aconitifolia (Jacq.) Maréchal (moth bean). There has been confusion on the taxonomic status of Vigna mungo and Vigna radiata; because they are closely related it was proposed that they be grouped into a single species. However, at present they are considered as 2 separate species with as major differences: flower colour (bright yellow in Vigna mungo, pale yellow in Vigna radiata), pocket on the keel (longer in Vigna mungo than in Vigna radiata), fruit shape (pods of Vigna mungo are shorter and erect on the peduncle, in Vigna radiata the pods are longer and spreading or pendulous).
Three taxa are distinguished within Vigna mungo:
– var. mungo, with large, black-seeded and early-maturing cultivars;
– var. viridis Bose, with greenish dull or glossy seeds and late-maturing cultivars;
– var. silvestris Lukoki, Maréchal & Otoul, the wild type; compared to cultivated types it is smaller, more climbing, more hairy, with denser inflorescences and small seeds with prominent raised aril; it is considered the ancestor of the cultivated black gram.
For cultivated types a classification into cultivars and cultivar groups would be more appropriate.
Germination of black gram normally takes 7–10 days. Flowering starts 30–60 days after sowing. Flowers are normally self-pollinating, with the pollen shedding before the flower opens. Maturity is reached in 60–140 days after sowing. Black gram effectively nodulates with Bradyrhizobium bacteria.
Ecology
Black gram is basically a warm season crop, but in India it is grown in both summer and winter, up to 1800 m altitude. It is quite drought resistant but intolerant of frost and prolonged cloudiness. It is normally grown in areas with an average temperature of 25–35°C and an annual rainfall of 600–1000 mm. In higher rainfall areas it may be grown in the dry season on residual moisture. Heavier, well-drained soils such as black-cotton soils with pH 6–7 are preferred, but black gram is also grown on lighter soils.
Management
Black gram is propagated by seed. The 1000-seed weight is 15–60 g. It is sown broadcast or in rows at a depth of 1–1.5 cm. The seed rate is 10–30 kg/ha, space between rows 25–40 cm, space within the row 10–20 cm. Thorough field preparation is not required; rough tillage suffices. Weeding is done only once or twice until the canopy is established. The crop is mainly rainfed and fertilizer application is not common. In the wet season in India it is mainly intercropped, with sugar cane, cotton, groundnut, sorghum or pigeon pea as the main crops. In the dry season it is often sole cropped on rice fallow. Important diseases of black gram are mung bean yellow mosaic virus (MYMV), Cercospora leaf spot (caused by Cercospora sp.), web blight (Rhizoctonia solani, synonym: Thanatephorus cucumeris) and powdery mildew (Erysiphe polygoni, synonym: Erysiphe betae). The most serious pests are white fly and thrips. In storage the seeds are attacked by bruchids (Callosobruchus spp.). Black gram must be harvested before the pods are fully ripe to prevent shattering. The plants are cut or uprooted, stacked to dry for up to 7 days, and threshed by beating with sticks or animal trampling. Alternatively, the pods may be handpicked. Yield of dry seed averages 350–800 kg/ha but it can reach 1500–2500 kg/ha. In India black gram seeds are usually processed into split seeds (dhal).
Genetic resources and breeding
About 2100 accessions of black gram are maintained by the National Bureau of Plant Genetic Resources (NBPGR), New Delhi, India, at its various research stations. The USDA Southern Regional Plant Introduction Station, Griffin, Georgia, United States, holds 300 accessions, and the Asian Vegetable Research and Development Centre (AVRDC) in Taiwan maintains a collection of 200 accessions. Breeding programmes for improvement of this pulse aim for a plant type combining determinate growth habit with a plant height of 30 cm, early maturity (60–90 days), and suitability for many different agroclimatic regions. Sources of resistance against most current diseases are available and several resistant cultivars have been released. Genetic variability of black gram is great, allowing development of suitable cultivars for most tropical and subtropical climates. Genetic transformation of black gram has been achieved using Agrobacterium -mediated transfer.
Prospects
It would be worthwhile trying black gram on a much larger scale in tropical Africa because of its highly nutritious seeds and its wide ecological applicability. Germplasm diversity needs to be exploited to obtain suitable cultivars for Africa.
Major references
• Arora, R.K. & Shri S. Mauria, 1989. Vigna mungo (L.) Hepper. In: van der Maesen, L.J.G. & Somaatmadja, S. (Editors). Plant Resources of South-East Asia No 1. Pulses. Pudoc, Wageningen, Netherlands. pp. 70–71.
• Dikshit, H.K., Gupta, S., Gupta, S.R. & Singh, R.A., 2004. Variability and its characterization in Indian collections of blackgram (Vigna mungo (L. ) Hepper). Plant Genetics Resources Newsletter 127: 20–24.
• Kay, D.E., 1979. Food legumes. Crops and Product Digest No 3. Tropical Products Institute, London, United Kingdom. 435 pp.
• Lawn, R.J. & Ahn, C.S., 1985. Mung bean (Vigna radiata (L.) Wilczek / Vigna mungo (L.) Hepper). In: Summerfield, R.J. & Roberts, E.H. (Editors). Grain legume crops. Collins, London, United Kingdom. pp. 584–623.
• Souframanien, J. & Gopalakrishna, T., 2004. A comparative analysis of genetic diversity in blackgram genotypes using RAPD and ISSR markers. Theoretical and Applied Genetics 109: 1687–1693.
Other references
• CSIR, 1976. The wealth of India. A dictionary of Indian raw materials & industrial products. Raw materials. Volume 10: Sp–W. Publications and Information Directorate, Council of Scientific and Industrial Research, New Delhi, India. 591 pp.
• Ghafoor, A., Sharif, A., Ahmad, Z., Zahid, M.A. & Rabbani, M.A., 2001. Genetic diversity in blackgram (Vigna mungo (L.) Hepper). Field Crops Research 69: 183–190.
• Gillett, J.B., Polhill, R.M., Verdcourt, B., Schubert, B.G., Milne-Redhead, E., & Brummitt, R.K., 1971. Leguminosae (Parts 3–4), subfamily Papilionoideae (1–2). In: Milne-Redhead, E. & Polhill, R.M. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 1108 pp.
• Haytowitz, D.B. & Matthews, R.H., 1986. Composition of foods: legumes and legume products. Agriculture Handbook No 8–16. United States Department of Agriculture, Washington, D. C. , United States. 156 pp.
• ILDIS, 2005. World database of Legumes, Version 9,00. International Legume Database & Information Service. [Internet] http://biodiversity.soton.ac.uk/LegumeWeb. Accessed September 2005.
• Maréchal, R., Mascherpa, J.-M. & Stainier, F., 1978. Etude taxonomique d’un groupe complexe d’espèces des genres Phaseolus et Vigna (Papilionaceae) sur la base de données morphologiques et polliniques, traitées par l’analyse informatique. Boissiera 28: 1–273.
• Midya, A., Bhattacharjee, K., Ghose, S.S. & Banik, P., 2005. Deferred seeding of blackgram (Phaseolus mungo L.) in rice (Oryza sativa L.) field on yield advantages and smothering of weeds. Journal of Agronomy and Crop Science 191: 195–201.
• Purseglove, J.W., 1968. Tropical Crops. Dicotyledons. Longman, London, United Kingdom. 719 pp.
• Saini, R. & Jaiwal, P.K., 2005. Transformation of a recalcitrant grain legume, Vigna mungo (L.) Hepper, using Agrobacterium tumefaciens-mediated gene transfer to shoot apical meristem cultures. Plant Cell Reports 24(3): 164–171.
• Srivastava, A. & Joshi, L.D., 1990. Effect of feeding black gram (Phaseolus mungo) on serum lipids of normal and diabetic guinea pigs. Indian Journal of Medical Research, section B: 92: 383:386.
Sources of illustration
• Arora, R.K. & Shri S. Mauria, 1989. Vigna mungo (L.) Hepper. In: van der Maesen, L.J.G. & Somaatmadja, S. (Editors). Plant Resources of South-East Asia No 1. Pulses. Pudoc, Wageningen, Netherlands. pp. 70–71.
Author(s)
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Based on PROSEA 1: ‘Pulses’.

Editors
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
G. Belay
Ethiopian Agricultural Research Organization, Debre Zeit Center, P.O. Box 32, Debre Zeit, Ethiopia
Associate editors
J.M.J. de Wet
Department of Crop Sciences, Urbana-Champaign, Turner Hall, 1102 South Goodwin Avenue, Urbana, IL 61801, United States
O.T. Edje
Faculty of Agriculture, University of Swaziland, P.O. Luyengo, Luyengo, Swaziland
E. Westphal
Ritzema Bosweg 13, 6706 BB Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Photo editor
A. de Ruijter
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Jansen, P.C.M., 2006. Vigna mungo (L.) Hepper In: Brink, M. & Belay, G. (Editors). PROTA 1: Cereals and pulses/Céréales et légumes secs. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, part of fruiting branch; 2, flower; 3, seed.
Source: PROSEA