Cross-compatibility of cultivated cowpea varieties and their wild relatives: Implications for crop improvement

Hybridization programmes that potentially exploit the variability existing in the wild germplasm of Vigna unguiculata L. Walpers could be of great potential for the future of plant breeding. Bearing this in mind, four cultivated cowpea varieties (Achi shuru, Ife Brown, Kanannado and Zebra bean) were crossed to two of their wild relatives: subsp. dekindtiana var. pubescens and subsp. unguiculata var. spontanea to ascertain the cross compatibility, reproductive potential and possible heterosis in the F1 generations. Results showed that the cultivated varieties hybridized relatively well with their wild relatives showing pod set range of 42.9% to 52.3% in crosses with subsp. dekindtiana var. pubescens and 40.0% to 52.0% in crosses with subsp. unguiculata var. spontanea. The F1 hybrid plants showed high heterosis in plant height, number of leaves per plant, number of flowers per plant, number of pods per plant and percentage pod set. They also produced viable seeds for F2 generations. These results are indications of a good reproductive potential of the hybrids thus making the wild relatives, good sources of important gene pool for the improvement of the cultivated populations.