Vigna mungo (PROSEA)
Vigna mungo (L.) Hepper
- Protologue: Kew Bull. 128 (1956).
- Family: Leguminosae
- Chromosome number: 2n= 22
- Phaseolus mungo L. (1767), non Roxb. (1832) & auct. mult.
- Black gram, urd bean (En)
- haricot mungo, ambérique (Fr).
Origin and geographic distribution
A primary gene centre of black gram is found in India, and a secondary centre in Central Asia. In South-East Asia black gram is cultivated in North Malaysia, the Philippines, Thailand and Burma. It is also cultivated in Bhutan, Nepal, Bangladesh, Afghanistan, Iran, Kenya, Malawi and the USA, but it is of major importance in India only.
Black gram is used as a pulse, direct or in various preparations for human consumption. Small quantities are used as cattle feed. It has some use as green manure crop and in medicine.
Production and international trade
In India, the major producer, average production and area cultivated in the period 1980-1985 were 1 070 000 t/year and 2 996 000 ha/year respectively. In India black gram is grown for local consumption. Thailand is the second producer and dominates world trade.
Dry seeds contain per 100 g edible portion: water 10 g, protein 22-24 g, fat 1-2 g, carbohydrates 56-60 g, fibre 0.9 g, ash 3.2 g. The energetic value averages 1445 kJ/100 g. Seed weight varies between 1.5 and 4 g/100 seeds.
- An erect, hairy annual, 30-100 cm tall, sometimes twining; stem diffusely branched from the base, furrowed.
- Leaves trifoliolate, petiole 6-20 cm long; leaflets ovate or rhombic-ovate, 4-10 cm x 2-5 cm, entire, acuminate.
- Flowers small and yellow, in axillary racemes on initially short but later elongating (up to 18 cm) peduncles; bracteoles linear to lanceolate, exceeding the calyx; corolla yellow with spirally coiled keel with a terminal horn-like appendage.
- Pods subcylindrical, 4-6 cm long, with long hairs and short hooked beak.
- Seeds 4-10 per pod, ellipsoid, with square ends and concave, raised hilum, usually black or mottled.
Germination in 7-10 days. Vegetative growth up to 50-60 days and maturity is reached in 90-120 days after sowing. Germination is epigeal.
Three varieties are distinguished:
- var. mungo, with large, black-seeded and early-maturing types;
- var. viridis Bose, with greenish dull or shining glossy seeds and late maturing types;
- var. silvestris Lukoki, Maréchal & Otoul, a wild type occurring in open shrub-land (scrub) vegetation in the Western Ghats and northern hilly tracts of Maharashtra, India, in partly humid tropical habitats.
The wild plant is viny, more hairy, with denser umbels and small seeds as compared to cultivated types with prominent, raised hilum. For the cultivated forms (the first two varieties) a classification into cv.-groups would be more appropriate.
Black gram is basically a warm season crop, but it is grown in both summer and winter season in India, depending upon the absence of frost. Heavier soils like black-cotton soils are preferred. It is quite drought resistant but intolerant of frost and prolonged cloudiness. Black gram tolerates a precipitation of ca. 530-2430 mm/year, an annual mean temperature of 8-28 °C and a pH of 4.5-7.5. Optimum temperature ranges from 25-35 °C, yields are reasonable with a precipitation of 650-900 mm/year.
Black gram is propagated by seed, sown broadcast or in rows. It does not require thorough field preparation, rough tillage suffices. Weeding is done only once or twice. The crop is mainly rainfed and fertilizer application is not common. Important diseases are leaf spot (caused by Cercospora sp.) and yellow mosaic virus. Pests are caused by a.o. aphids, bugs and weevils. In storage the seeds are attacked by bruchids (Callosobruchus chinensis).
Black gram is to be harvested before the pods are fully ripe to prevent shattering. Seeds are processed in the form of split seeds (dhal).Yield of dry seed averages 340-560 kg/ha but it can reach 1500 kg/ha.
Genetic resources and breeding
Genetic diversity is narrower than in green gram. The AVRDC in Taiwan maintains a collection of 200 entries (1980). About 1900 accessions are maintained by the National Bureau of Plant Genetic Resources, Delhi, at its various research stations. Breeding programmes for improvement of this nutritious pulse have not been commensurate with the importance in the Indian diet. Systematic and planned work for improvement started in India in the early 1940s. Over 40 cultivars, both erect and spreading types, are grown in different agro- climatic regions of India. Sources of resistance against most current diseases are available and progress is being made by AVRDC to incorporate these traits.
Black gram is a promising crop for the South-East Asian region. It is highly nutritious and its ecological applicability is wide. Germplasm diversity needs to be exploited in the South-East Asian countries.
- Anonymous, 1976. The wealth of India. CSIR, New Delhi. Vol. 10: 476-484.
- Duke, J.A., 1981. Handbook of legumes of world economic importance. Plenum Press, New York & London. p. 291-293.
- R.K. Arora & Shri S. Mauria