Genotype by environment interactions of twenty accessions of cowpea [Vigna unguiculata (L.) Walp.] across two locations in Nigeria

The genotype × environment interaction (GxE) is a serious problem when comparing the performance of crop genotype across environments because it reduces the efficiency of the genetic gain through selection. GxE is said to occur when the relative performance of the crop genotype is not consistent from one environment to another. The purpose of the study is to use genotype-focused scaling for genotypic comparison and environment-focused scaling for environmental comparison. Yield data component were determined from 20 accessions of Cowpea from Nigeria across two locations during year 1 and year 2 planting seasons to study the effect of environment on genotype. Ten quantitative traits were analyzed and yield component, such as weight of seed in pod, weight of 100 seed/plant, number of seed/pod, pod length, and number of pods/plant, were measured and subjected to statistical analysis. From the result obtained, there were significant differences in weight of seed in pod, weight of 100 seed/plant, number of seed/pod, pod length, and number of pods/plant, having 0.084, 11.638, 13.182, 9.390, and 51.911 at P ≤ 0.01 across the two locations. The study revealed a significant effect of environment on yield component among the genotypes. However, the most stable genotypes across the two locations were NG/SA/07/083, NG/SA/DEC/07/035, and NG/SA/07/0042.