Crossability and inheritance of seed coat colour in cowpea at F1 generation

A study on crossability and inheritance of seed coat colour in cowpea was conducted between October, 2017 and August, 2018. Two accessions of cowpea: IT98K-205-8 (white seeded) and IT98K-555-1 (brown seeded) were used for the study. Plants were raised in plastic pots in the screen house, and as flowers mature, crosses were performed manually, early in the morning between 7.00 and 9:30 AM. Significant level of differences were detected between the crosses for all traits observed except for number of seeds per pod. Overall, 19 successful pods were generated from 67 crosses representing 28.36% success rate, and indicating a low level of compatibility between accessions. All seeds of F1 plants were black, contradicting the model that maternal parents determine the phenotypes of F1s. However, the two parents bred true for seed coat colour indicating their pure line status. It was shown that maternal effect played significant role regarding crossability, but did not influence the seed coat colour inheritance of the crop. These results indicated epistasis, and it is suggested that the inheritance of seed coat colour in cowpea is polygenic.