Multivariate stability statistics of genotype by environment interaction on fresh yield of cowpea.

The current study aims to assess the ten cowpea genotypes that are stable and adaptive under three locations during the growth seasons of 2021, 2022, and 2023 using multivariate stability statistics. The fresh cowpea yield (t/ha) using combined ANOVA and AMMI analysis revealed that the environment is the most important factor and that variations between genotypes, environment, and genotype by environment interaction (GEI) were significant (p < 0.01). Eight main component axes (PCs) were obtained from the sum of squares of the GEI component. The mean squares for the first five PCs were significant (p < 0.05 or 0.01). The Sids location boosted the fresh cowpea yield (t/ha) of every genotype studied throughout all growing seasons, with Sakha and Ismailia locations coming in second and third, respectively. In terms of fresh cowpea yield, the G3 genotype produced the highest mean response, but with moderate stability in the nine environments conditions. G7 was the most stable genotype, with the least amount of yield variation across nine conditions, and was identified by AMMI-based stability parameters. Additionally, according to AMMI and GGE biplot analysis, G7 and G2 genotypes showed excellent stability. Most pairs of AMMI-based stability metrics under study had significant rank correlation coefficients (P < 0.05 or 0.01) in a positive direction. Using a GGE biplot polygon of "which-won-where", the environments were separated into two mega-environments. Using the AMMI model and GGE biplot analysis, the environments E4, E5, and E9 had the longest vectors and the highest fresh cowpea yield (t/ha). To guarantee sustainable progress in cowpea production systems, the study emphasizes the necessity of using a multidimensional strategy for genotype evaluation. This will allow breeders to make well-informed decisions for resilience and productivity under a variety of environmental situations. This raises the prospect of concurrent indirect selection of these traits to take advantage of GEI and increase Egypt's production of fresh cowpeas.