Abstract

Field experiments were conducted in 2006 and 2007 to estimate genetic variability, heritability, correlations and path analysis of some reproductive characters on grain yield of 10 cowpea accessions. The experiment was laid out in a Randomized Complete Block Design (RCBD) at the research farm, University of Nigeria, Nsukka. The accessions showed significant (p<0.05) variability for days to 50% flowering, number of peduncles plant^-1, flowers plant^-1, pods plant^-1, seeds pod^-1, pod length, 100-seed weight and grain yield. The magnitudes of the genotypic variance of these traits were higher than the environmental variance, indicating that the genotypic component was the major contributor to total variance. Phenotypic coefficient of variation and genotypic coefficient of variation were high for the traits studied, except pod length and seeds pod^-1. High broad-sense heritability (63.16 - 96.74%) indicated the presence of additive gene effects. Positive correlation were found between grain yield and number of peduncles plant^-1 (r = 0.716**), flowers plant^-1 (r = 0.776**), pods plant^-1(r = 0.640*) and 100-seed weight (r = 0.690*). Path analysis showed high positive direct effects of number of peduncles plant^-1 (p = 0.94), flowers plant^-1 (p = 1.40) and 100-seed weight (p = 1.45). Numbers of peduncles plant^-1, flowers plant^-1, pods plant^-1 and 100-seed weight were identified as selection criteria for obtaining good parental lines in cowpea breeding programs.

Key words: Accession, additive effects, cowpea, path analysis, variability.