Abstract

The grain yield components of eleven cowpea genotypes were studied in 2006 and 2007 at Abeokuta, Nigeria, to understand the sensitivity of the quantitative traits to heterogeneous environments. The genotypes differ significantly (p ≤ 0.05) in grain yield; the pods/plant and Dfodyld equally differed significantly for the two years. Significant (p ≤ 0.05) genotypic variation in pod length was only in 2007. DT50F, DT95M, 100 seed weight and pod yield were significantly (p ≤ 0.05) influenced by the effect of genotype, year and their interactions. Seeds/pod, 100 seed weight and pod length had fairly high relative genetic gain resulting from high GCV: PCV, heritability and repeatability; indicating their low sensitivity to G × E. Loss of potential genetic gain was 26% in pod yield  and 24% in seeds/pod. IT97K - 499 - 35, IT97 - 568 - 18 and IT95K - 2011 - 11 were identified in this study as the genotypes with high productivity and good genetic stability for pod yield, seeds/pod and 100 seed weight, respectively.

Key words: Variances, heritability, repeatability, loss of potential genetic gain, stability.