Adzuki bean

The adzuki bean (name from azuki (Japanese: アズキ, sometimes アヅキ（小豆); Vigna angularis; also azuki bean, aduki bean, red bean, or red mung bean), is an annual vine widely cultivated throughout East Asia for its small (approximately 5 millimetres (0.20 in) long) bean. The cultivars most familiar in East Asia have a uniform red color, but there are also white, black, gray, and variously mottled varieties.

Scientists presume Vigna angularis var. nipponensis is the progenitor.[1]

The wild ancestor of cultivated adzuki bean is probably Vigna angularis var. nipponensis,[2] which is distributed across Japan, Korea, China, Nepal and Bhutan.[3] Speciation between Vigna angularis var. nipponensis and Vigna angularis var. angularis occurred around 50,000 years ago.[4] Archaeologists estimate it was domesticated around 3000 BC.[5] However, adzuki beans (as well as soybeans) dating from 3000 BC to 2000 BC are indicated to still be largely within the wild size range. Enlarged seeds occurred during the later Bronze Age or Iron Age, periods with plough use.[6] Domestication of adzuki beans resulted in a trade-off between yield and seed size. Cultivated adzuki beans have fewer but longer pods, fewer but larger seeds, a shorter stature, and also a smaller overall seed yield than wild forms.[3] The exact place of domestication is not known;[2] multiple domestication origins in East Asia (for example Japan, China, and Korea) have been suggested.[5]