Integrating Multi-Trait Selection and Environmental Stability for Soybean (Glycine max L. Merr.) Genotype Improvement...

Soybean (Glycine max L. Merr.) is a critical crop for food security and economic development in tropical regions, particularly in Indonesia. Despite its importance, the productivity of soybean in these areas is hindered by challenging climatic conditions, leading to a reliance on imports from temperate regions. Here, we identify genotypes that exhibit superior agronomic traits and stability, thereby contributing to improved soybean productivity in tropical environments. The multi-trait genotype-ideotype distance index (MGIDI) and multi-trait stability index (MTSI) were employed to evaluate the genotypes' performance in relation to an ideal ideotype and their stability across the environments. Additionally, the Genotype Main Effect Plus G × E Interaction (GGE) Biplot analysis was utilised to examine genotype-by-environment interactions and to identify the most suitable environments for soybean cultivation. The MGIDI index analysis identified the 100-seed weight (W100) as a key trait with the highest selection gain. The MTSI identified genotypes G11, G18 and G14 as the most stable across all environments. The GGE Biplot analysis indicated E2 (Upland, rainy season) as the most ideal environment for selecting superior soybean genotypes, suggesting it is the optimal setting for future breeding efforts. This study highlighted the importance of multi-trait selection and stability analysis in identifying soybean genotypes with both desirable traits and environmental stability for diverse tropical conditions. These findings offer strategic insights for future soybean breeding and cultivation in tropical regions.