Evaluation of Some Cowpea (Vigna Unguiculata L. [Walp]) Genotypes for Stability Of Performance Over 4 Years

Abstract

Genotype × environment interaction (GEI) plays a significant role in determining the desirability or superiority of a genotype, hence the need to evaluate genotypes over wide range of environment. Seven improved cowpea genotypes were evaluated in four environments (years); the late seasons of 2009, 2010. 2011 and 2012 to determine their desirability based on mean grain yield and stability in Abeokuta Southwestern Nigeria using the Genotype+Genotype×environment (GGE) biplot. IT98K-573-2-1 had the highest mean grain yield while IFE-98-12 had the lowest. There was highly significant Genotype × Environment Interaction on seed yield (p<0.001) indicating the need for GEI analysis. The GGE biplot identified three mega-was low yielding. IT98K-573-2-1 was selected as the best combiner of high yield and stability and the most desirable for Abeokuta Southwestern Nigeria. AB10 was identified as the best among the test environments. This study documents the responses of improved cowpea genotypes to different environments. Genotype by environment interaction continues to have high implications in plant breeding. IT98K-573-2-1 was identified as a well buffered genotype and therefore desirable for selection for further improvement.