Biometrical approaches for selection of parents in vegetable cowpea (Vigna unguiculata) breeding programme

Abstract

Eighty nine genotypes of vegetable cowpea collected from different parts of India were evaluated for yield and yield-attributing traits for genetic variation, character association, cause-effect analysis and genetic diversity among the genotypes through D2 statistics. High values of genotypic and phenotypic coefficient of variations, broad sense heritability and genetic advance were estimated for plant height, pod yield/plant, number of peduncles and pods/plant, pod weight and pod length. Pod yield/plant showed strong positive correlation with pod weight, number of peduncles and pods/plant, pod length and number of seeds/pod, while negative correlation with days to 50% flowering at genotypic and phenotypic levels. The maximum direct positive effect on pod yield/plant was contributed by pod weight followed by number of pods/plant. Based on degree of divergence the genotypes were grouped into twelve clusters. The genotypes of cluster XII showed maximum genetic divergence with cluster X, hence, crossing between genotypes within these groups could produce good recombinants and desirable segregants. Cluster III was found to be the best performing for number of pods/plant, pod weight and pod yield/plant while the cluster IX flowered much earlier. Thus, crossing between genotypes within these groups could produce desirable transgressive segregants for earliness and high yielding genotypes. Plant height contributed highest towards divergence (29.37%) followed by number of peduncles/plant (26.30%), number of pods/plant (18.39%) and pod weight (16.42%) among vegetable cowpea genotypes.