Genotype × environment interaction and adaptation of cowpea genotypes across six planting seasons

Cowpea exhibits significantly inconsistent performances across different environments, and hence demands performance evaluation of genotypes prior release or cultivation in every breeding program. Hence, the goal of this study was to compare 16 cowpea genotypes over six planting seasons (2014-2019) in Akungba-Akoko, Nigeria for their stability and adaptation through Finlay and Wilkinson (FW), Additive Main Effects and Multiplicative Interaction (AMMI) and Genotype and Genotype × Environment (GGE) analyses. ANOVA revealed high significant genotype (15.33%), environment (14.71%) and GEI (64.34%) effects for seed yield among genotypes. All analyses were able to pinpoint stable high-yielding genotypes including G14 and G9. Genotypes G14, G3, G4, G5, G6 and G9 were high yielding and stable according to FW; AMMI showed G10, G9, G16, G14 and G13 stable high-yielding while GGE showed G14, G16, G9 and G13 as stable high-yielding. As analyses explored the variation in the data due to GEI, they also complemented one another, in that where one erroneously included a wrong genotype as stable; the other excluded such genotype, making recommendation possible on the basis of consistency to gain reliability.