Biometrical studies of yield and related traits in advance breeding lines of bush type vegetable cowpea [Vigna unguiculata (L.) Walp.]

Sixty-six bush type advance breeding lines of vegetable cowpea developed at ICAR - Indian Institute of Vegetable Research (ICAR-IIVR), Varanasi were evaluated for different horticultural traits for genetic variability, character association, cause-effect analysis and genetic diversity among the genotypes through D2 statistics. High values of genotypic and phenotypic coefficient of variations, heritability (h2B) and genetic advance were recorded for pod yield per plant, number of peduncles and pods per plant, peduncle length, number of primary branches per plant, pod length, pod weight and number of seeds per pod. Pod yield per plant showed strong positive correlation with number of peduncles and pods per plant, pod weight, pod length, number of seeds per pod and number of primary branches per plant, while negative correlation with days to 50% flowering at genotypic and phenotypic levels. The maximum direct positive effect on pod yield per plant was found contributed by number of pods per plant followed by pod weight. Based on degree of divergence the genotypes get grouped into seventeen clusters. The top three characters which contributed most towards the genetic divergence were number of peduncles per plant, peduncle length and pod length. The genotypes of cluster VII showed maximum genetic divergence with genotypes of cluster VIII. Further, cluster VII had the high yielding genotypes, while cluster XVII had early flowering genotypes. Thus, crossing between genotypes of these groups may result in high yielding early genotypes.