Assessing genetic variability and identifying stable soybean (Glycine max L.) genotypes across rainfed and irrigated planting conditions using multi-trait stability index (MTSI)

This study assessed genetic variability and identified stable soybean (Glycine max L.) genotypes suitable for rainfed and irrigated conditions in central India to enhance soybean breeding programs. Advanced breeding lines were evaluated using a randomized complete block design, with phenotypic assessments analyzing genetic variability, associations, and stability through multiple regression and multi-trait stability index (MTSI). The phenotypic coefficient of variation (PCV) exceeded the genotypic coefficient of variation (GCV) for all traits. High heritability combined with significant genetic advance was observed for pods per plant, seeds per plant, seed weight, biological yield, and seed yield. Positive associations of biological yield and harvest index with seed yield were consistent across conditions. Path analysis identified biological yield as having the highest direct effect on seed yield. MTSI identified JS 22-101 as the most stable genotype for both conditions, with JS 22-77 and JS 22-78 performing well under rainfed and irrigated conditions, respectively. Biological yield emerged as the primary yield-contributing trait, highlighting the need to refine selection criteria for soybean breeding programs.