Trait dissection for yield enhancement in rabi Soybean (Glycine max L.) using principal component and regression analyses

Abstract

Soybean (Glycine max L.) is predominantly grown as a kharif crop in Telangana, where it demonstrates substantial yield potential. With its growing significance as a major oilseed crop and its proven role in enhancing the livelihoods of farmers, there is increasing interest in extending its cultivation to the rabi season. Despite its agronomic and economic promise, rabi soybean remains underexploited, primarily due to the absence of high-yielding, season-specific varieties adapted to off-season conditions. To address this gap, the present study was undertaken to dissect yield-contributing traits and identify promising genotypes for rabi soybean improvement. Fifty diverse soybean genotypes were evaluated during the first fortnight of November 2022 at the Regional Sugarcane and Rice Research Station, PJTSAU, Rudrur, using an alpha lattice design with two replications. Analysis of variance revealed significant genotypic variability for all the traits except seeds per pod, indicating substantial scope for genetic gain through selection. Correlation analysis, principal component analysis (PCA), and stepwise multiple regression collectively highlighted number of pods per plant as the most critical determinant of seed yield under rabi conditions. The traits number of pods on the main stem, plant height, days to 50% flowering, days to maturity, and 100-seed weight also exhibited strong associations with yield and should be given due consideration in selection strategies. PCA revealed that the first two principal components accounted for 57.7% of the total phenotypic variation, effectively capturing the major patterns of trait diversity. Based on multivariate analysis, five genotypes; G21, G5, G42, G25, and G3 were identified as genetically divergent and agronomically promising, offering valuable resources for parental selection and future breeding programs aimed at enhancing rabi soybean productivity.