Evolution of Grain Legumes. III. Pulses in the Genus Vigna

Abstract

SUMMARYThe genus Vigna includes seven species of pulse, two African and five Asian. While the Asian species are within the subgenus Ceratotropis, the two African species are in different sections of the subgenus Vigna, namely Catjang (V. unguiculata) and Vigna (V. subterranea). Limited gene flow is possible within subgenus Ceratotropis, but none has as yet been demonstrated between subgenera nor between sections within subgenus Vigna. Parallel evolutionary trends are apparent in all species, with considerable increase in seed and pod size. Erect bush forms have evolved in all cultigens except V. aconitifolia and V. subterranea. The former has not apparently changed much in vegetative form under domestication, while the geocarpy of the latter precludes erect growth. Future prospects for the Asiatic grams would be better if yield levels could be improved. The cowpea is likely to remain an important crop at present levels of performance although there is room for improvement. There seems little immediate prospect of expanded ground bean production under existing conditions.