Delineating G × E interactions by AMMI method for yield attributes in cowpea (Vigna unguiculata(L.) Walp.)

Cowpea can tolerate a wide range of climate conditions. Despite this, crop yields are often low due to a lack of stable, drought-tolerant varieties. The additive main effects and multiplicative interactions (AMMI) model was used in the current study to examine how cowpea genotypes responded to environmental conditions based on variations in yield and its contributing factors. The experiment used a randomized complete block design with three replications over two consecutive years at six locations. Over multiple harvests, yield and its component traits such as the total number of pods per plant, pod length (cm), hundred seeds weight (g), and yield per hectare were evaluated in the rainy season in 2020 and 2021. Stability tests for multivariate stability parameters were performed based on analyses of variance. For all the traits, the pooled analysis of variance indicated highly significant (p < 0.01) variations between genotypes, environments, and genotypes by environment (GEI). Furthermore, the first, second, and third main component axes (IPCA1, IPCA2, and IPCA3) explained most of the GEI for these attributes. AMMI1 and AMMI2 biplot analyses showed differential stability of genotypes for yield and its component traits with few exceptions. The best genotype, according to the ideal genotype ranking, was genotype KGC 1. Genotypes KGC5 and KGC2, on the other hand, had high yields that were especially suited to the LAD environment during the 2021 growing season. Location-specific adaptation of genotypes indicates that location-specific breeding needs to be undertaken along with the focus on wider adaptability.