**Taxonomy and Genetics:**
– Cultivated Asiatic Vigna species belong to sub-genus Ceratotropis with chromosome number of 2n = 22.
– Seven cultivated species within the sub-genus include mung bean, black gram, adzuki bean, and moth bean.
– Artificial crosses made between V. mungo and V. umbellata to produce improved mung bean varieties.
– Three secondary gene pools within the group, with ricebean closer to V. angularis.
– Ricebean is in the Angulares group.
**Origin, Distribution, and Adaptation:**
– Ricebean’s distribution ranges from humid tropical to sub-temperate climates.
– Presumed center of domestication is Indo-China.
– Derived from wild form V. umbellata var gracilis.
– Ricebean adapted to subhumid regions with 1000–1500mm precipitation.
– Tolerant to drought, high temperatures, and some waterlogging.
– Tolerant to acid soils and resistant to pests and diseases.
**Morphology and Germplasm Collections:**
– Wild forms are fine-stemmed, freely-branching, and small-leaved with a twining habit.
– Photoperiod sensitivity and indeterminate growth.
– Asynchronous flowering with a tendency to hard seeds.
– Seed color variable, commonly red or yellow.
– World Vegetable Centre, National Bureau of Plant Genetic Resources in India, Indian Institute for Pulses Research, and Plant Genetic Resources Unit of the NARC in Nepal hold significant collections of ricebean germplasm.
**Nutrition and Usage:**
– Ricebean is commonly served as dal in various recipes.
– Pulses are used whole, cooked, roasted, as flour, or ground for dishes.
– Green pods are consumed as a vegetable in some regions.
– Ricebean contains antinutrients like phytic acid, impacting iron and zinc uptake.
– Valuable fodder for livestock, increasing milk production.
**Cultural Significance, Potential, and Chemistry:**
– Ricebean is categorized as a cold or hot food based on location.
– Used in traditional Nepali dishes like kwati during festivals.
– Ricebean has untapped potential requiring attention from breeders.
– Ricebean can be used as a green manure crop due to high biomass production.
– Catechin-7-O-glucoside, an antioxidant, is found in ricebean seeds.