Journal of Advances in Biology & Biotechnology

Developing high-yielding, locally adapted cultivars requires a precise understanding of genetic architecture and trait associations to overcome the yield plateau in soybean (Glycine max L. Merrill). This study evaluated 40 diverse soybean genotypes during Kharif 2022 at the Agricultural Research Station, Kota, Rajasthan, to quantify genetic variability, interrelationships and direct and indirect contributions of 13 quantitative and quality attributes. Analysis of existing genetic and correlation literature guided the experimental framework, and the data were analysed using a randomised block design (RBD) and path coefficient models. The genotypic correlation coefficients were generally higher in magnitude than the corresponding phenotypic correlation coefficients, indicating that the estimated associations among traits were comparatively stronger at the genotypic level. However, these differences alone do not establish the extent of environmental influence on trait expression. Seed yield per plant exhibited significant positive associations (p < 0.01) with 100-seed weight (r_g = 0.848), seeds per pod (r_g = 0.803), biological yield (r_g = 0.788), branches per plant (r_g = 0.726), pods per plant (r_g = 0.700), pod length (r_g = 0.648), harvest index (r_g = 0.597) and oil content (r_g = 0.465). Path coefficient analysis revealed that biological yield (genotypic direct effect: 1.422) and harvest index (0.862) were showing direct positive effect on seed yield, whereas 100-seed weight and seeds per pod influenced yield predominantly through indirect biomass-mediated pathways. Low residual effects (r_g = 0.070, r_p = 0.308) confirmed the high explanatory power of the model. Genotypes AUKS-22-34, AUKS-22-51, AUKS-22-37 and AUKS-22-35 were identified as superior donors. Overall, breeding programmes should prioritize simultaneous selection for total biomass accumulation, harvest index and reproductive architecture to accelerate soybean yield improvement.