Closely related to Vigna radiata[
]. 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)[
Azukia mungo (L.) Masam.
Phaseolus hernandezii Savi
Phaseolus mungo L.
Phaseolus radiatus Roxb.
Phaseolus roxburghii Wight & Arn.
Common Name: Black Gram
Black gram is an erect, hairy, bushy, annual plant with a well-developed taproot, growing 30 - 100cm tall. The stem is diffusely branched from the base. Sometimes the plant adopts a twining habit[
The plant is often cultivated in many areas of the tropics, especially Asia, for its edible seed[
]. It is also sometimes used medicinally and as a source of soap, as well as being grown as a green manure crop.
E. Asia - the exact original wild range is unknown.
Not known in a truly wild situation.
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A plant of the drier tropics, where it is found at elevations up to 2,000 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 35°c, but can tolerate 8 - 40°c[
]. The plant does not tolerate frost. It prefers a mean annual rainfall in the range 650 - 900mm, but tolerates 530 - 2,430mm[
]. Rain at flowering time has a very adverse effect upon seed yields[
]. Plants are not adapted to wet, humid areas with high rainfall, but can, however, be grown in the dry season of wetter areas so long as this is at least 4 months in duration[
Requires a sunny position[
]. Grows well in well-drained, fairly heavy fertile soils[
]. Tolerant of moderate levels of salt in the soil[
]. Prefers a pH in the range 5.5 - 6.5, tolerating 4.5 - 7.5[
]. Established plants are drought resistant[
Immature pods can be harvested about 60 - 80 days after sowing[
]. Mature beans can be harvested after 75 - 130 days[
Yields of 500 - 650 kilos per hectare of dried seeds can be obtained[
]. The average yield of dry seeds in India can vary between 340 - 1,500 kilos per hectare[
There are some named varieties[
There are three main forms of this plant:-
Var mungo. A large seeded, early maturing form with black seeds[
Var viridis Bose. A small seeded late maturing form with brown, green or grey seeds[
Ver silvestris Lukoki, Maréchal & Otoul. The original, wild form.
Most cultivars require short daylengths[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
]. When removing plant remains at the end of the growing season, it is best to only remove the aerial parts of the plant, leaving the roots in the ground to decay and release their nitrogen.
Young seedpods - cooked and used as a vegetable[
]. The seedpods are about 40 - 70mm long and 5mm wide[
Seeds - cooked[
]. The dried seeds are boiled and used in a variety of recipes[
]. They can also be ground into a flour as a protein enhancing additive to flour when making bread etc[
]. In India they are an essential ingredient of idli and dosa - acid-leavened fermented cakes make from rice and dhal[
]. The ellipsoid, usually black seed is up to 5mm long[
In traditional medicine, the seed is used for its suppurative, cooling and astringent properties. For example, it is ground into a powder, moistened and applied as a poultice on abscesses[
Plants are grown as a green manure[
In the wet season in India this species 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[
The seed flour is rich in saponins and can be used as a soap substitute[
]. It makes the skin smooth and soft[
Seed - presoak for 12 hours in warm water and sow in situ. The seed generally sprouts within 7 - 10 days[