Full Diallel Analysis and Combining Ability Study in Cowpea (Vigna Unguiculata (L.) Walp) For Yield and Its Related Components

Abstract

Crosses were made between the six parental lines of cowpea using the full diallel-crossing design to generate 15 crosses, 15 reciprocals and 6 parents were evaluated during the cropping season of 2024 and 2025 at Yola and Wukari, Nigeria in a randomized complete block design (RCBD) and replicated three times. Substantial variance existed among the genotypes, parental lines, crosses, and reciprocals for most of the agronomic traits. Both additive genetic effect and non-addictive gene effects controlled most traits, but non-addictive gene effects were significant and predominant as indicated by the predictability ratio of δ2GCA/δ2SCA which were less than one for all the traits. This work also identified Bossop, Bakwa and Sampea 18 as the best general combiner in term of GCA effects. Sampea 18 x Bossop, Sampea 19 x Bakwa, Bossop x Achishiru recorded the highest SCA effects for the crosses and the reciprocals Achishiru x Bossop and Bossop x Sampea 19 were found the best cross-combination. It was observed that most of crosses and reciprocals involved in this work with high SCA effect of crosses and reciprocal involve at least one of three high general combiners. The preponderance of non-additive genetic effect observed among the traits in the parents, the crosses and reciprocals studied is great tools in choosing the cowpea lines for biparental mating or reciprocal recurrent selection for developing superior genotypes with high yield.