Variability and association studies for yield and yield attributing traits in soybean (Glycine max (L.))

Abstract

The study was conducted during the rainy season of 2024 at the Agricultural Research Station, Adilabad, Telangana, to assess the extent of genetic variability and trait associations in 32 soybean genotypes (Glycine max (L.) Merr.). The experiment was laid out in a randomized complete block design with three replications. Analysis of variance revealed significant (P<0.01) and wide variability among the genotypes for all nine traits studied. High phenotypic and genotypic coefficients of variation were observed for plant height, number of branches per plant, and number of pods per plant, while moderate variation was noted for most other traits, except for flowering and maturity traits, which showed low variability. All traits exhibited high heritability, and all except flowering and maturity traits showed high genetic advance; the latter displayed moderate genetic advance. Phenotypic characterization demonstrated substantial variability among advanced breeding lines. Seed yield showed significant and positive correlations with 100-seed weight (0.797** phenotypic, 0.862** genotypic), plant height (0.461** phenotypic, 0.515** genotypic), and number of pods per plant (0.445** phenotypic, 0.470** genotypic). Path coefficient analysis indicated that 100-seed weight had the highest positive direct effect on seed yield (0.7752), followed by number of pods per plant (0.2733), plant height (0.2334), days to 50% flowering (0.1953), and number of seeds per pod (0.0642). These results suggested that these traits played a crucial role in influencing yield and should be given priority in direct and indirect selection for soybean improvement.