Germplasm evaluation and enhancement for the development of cowpea (Vigna unguiculata (L.) Walp) dual-purpose F2 genotypes.

Abstract

Cowpea is an important grain legume as well as fodder crop, especially in the dry regions of South Africa. The production of this crop has been below average because of low genetic variation and cultivation of poor-yielding varieties which have not been improved. The potentials of cowpea F2 generation arising from crosses made from 55 exotic parental lines, introduced into South Africa were determined. F1 lines derived from the crosses were advanced to F2 lines in the glass-house, and the segregating F2 families were further evaluated in the field with their parental lines. The following data were collected from the progeny: number of pods per plant, 100 seed-weights, fodder yield, grain yield and harvest index. Results showed that F2 lines exhibited significant differences on all the parameters studied thus indicating the presence of genetic variability among the segregating progeny. Number of pods per plant, 100 seed-weight and harvest index showed higher significant differences. The F2 lines obtained a significant increase in number of pods per plant as compared to their parents, thus indicating the potentials of progeny for higher pod production. Harvest index for F2 lines varied between 0.16 and 0.60 (dual-purpose type), and are mostly medium cowpea types with dual purpose characteristics for producing grain for human consumption and fodder for livestock. These parameters should therefore receive highest priority in developing high yielding dual-purpose varieties. There are several promising F2 progenies which performed exceedingly well over the parents, so further screening is essential until their full potential is attained. Key words: Vigna unguiculata, germplasm, harvest index, dual-purpose, 100 seed-weights, segregating population.