Some lines of one of the wild subspecies of cowpeas, Vigna unguiculata (L.) Walp. subspecies mensensis, which is characterized by large, conspicuous flowers, were found to set fruits poorly in the absence of a pollinator, whereas others, including cultivated lines, set well. These differences were related to the separation of anthers and stigma, the orientation of the stigmatic surface and the hairiness of the style, and differed from other outbreeding mechanisms reported in cowpeas. The results support division of wild cowpeas into two groups and suggest that an increase in the rate of inbreeding has accompanied their domestication.
- Faris, D. G. 1965. The origin and evolution of the cultivated forms ofVigna sinensis. Canad. J. Genet. Cytol. 7: 433–452.Google Scholar
- Howlett, F. S. 1939. The modification of flower structure by environment in varieties ofLycopersicon esculentum. J. Agric. Res. 58: 79–117.Google Scholar
- Piper, C. V. 1912. Agricultural varieties of the cowpea and immediately related species. U.S.D.A. Bur. PI. Industr. Bull. 229.Google Scholar
- Purseglove, J. W. 1968. Tropical Crops. Dicotyledons. Longman, London.Google Scholar
- -,K. O. Rachie, and J. D. Franckowiak. 1975. Reduction in seed size in crosses between wild and cultivatedVigna unguiculata (L.) Walp. Int. Inst. Tropical Agric. J. Series No. 50.Google Scholar
- Steele, W. M. 1972. Cowpeas in Nigeria. Ph.D. Thesis, Univ. Reading.Google Scholar
- Westphal, E. 1974. Pulses in Ethiopia, their Taxonomy and Agricultural Significance. Centre Agric. Publ., Wageningen.Google Scholar