Genetic variability and heritability of pod and seed characteristics in green beans (Phaseolus vulgaris)

Abstract

Thirty-nine green bean (Phaseolus vulgaris) genotypes were evaluated to determine the level of genetic variability and identify pod and seed traits that could be used as selection criteria for yield improvement. The evaluation was conducted at three out-stations of the Institute of Agricultural Research and Training, Nigeria, in 2023 using a 3 x 13 alpha lattice design in two replications. Data were collected on pod and seed parameters. Descriptive statistics, analysis of variance (ANOVA), genotypic (GCV) and phenotypic coefficient of variation (PCV), and correlation analysis were conducted. Genetic variances were estimated from mean squares of ANOVA. PCV estimates were higher than corresponding GCV. Range was high for some of the traits. Mean square of environment was significant for pod length, seed width and seeds/pod indicating the strong influence of environment on these traits. Mean square of genotypes was significant for seed length and seeds/pod. Estimate of environmental variance was slightly higher than genotypic variance estimate for all the traits. The value of genotypic variance was however high for 100 seed weight which also had high broad-sense heritability and high percentage expected gains. Broad-sense heritability and percentage expected gains were also high for pod length, seed length and number of seeds/pod indicating that these traits are under genetic control. Number of pods/peduncle had strong genotypic and phenotypic correlations with pod length, seed length and width, and number of seeds/pod, and strong phenotypic correlation with 100 seed weight. These traits also had strong correlations among themselves. This study revealed substantial genetic variability in the green bean collections for possible yield improvement. It also identified pod length, seed length, seeds/pod and 100-seed weight as reliable selection criteria for yield improvement in green bean under tropical environment.