Genetic variability, heritability, and genetic gain for yield and associated traits in recently introduced soybean genotypes in the Guinea Savannah zone of Ghana

Estimating genetic parameters optimizes the selection of complex traits. This study evaluated 150 soybean germplasm accessions from Ghana, Nigeria, USA and Colombia to assess the performance of recently introduced soybean genotypes for yield and associated traits. A 15 x 10 alpha lattice design with three replications was employed, each consisting of 10 incomplete blocks containing 15 genotypes. The results revealed significant genotypic differences among genotypes for all evaluated traits. Maturity days varied, with USA genotypes maturing earliest (82-115.33 days), followed by Colombia (97.33-136.00 days), IITA genotypes (106.67-142.0 days) and Ghana (114.00-135.33 days). Genotype PI 628866 (USA) exhibited the highest 100-seed weight (24.72 g). Ghanaian genotypes, including Favour, SAR-Qua/Afa-18-6, SAR-SL2/USL-18-2, SAR-SL2/SPg-18-3, and Afayak, recorded the highest grain yields (2.89-2.54 t/ha). The genetic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) ranged from 21 to 30% with high heritability estimates (>80%) observed for most traits, indicating strong potential for genetic improvement through selection. Correlation analysis showed strong associations: DFF-DM (r=0.79), GY-PHF (r=0.67), GY-PHM (r=0.55); a weak correlation was observed between GY-HSW (r=0.19). Moderate correlations were found for GY-PPP (r=0.37) and GY-terminal leaf length. PHF was identified as an effective selection criterion for GY, while a negative association between HSW and PHF suggests trade-offs. Multi-trait selection indices are necessary due to moderate correlations between GY and PPP. Path coefficient analysis identified days to flowering (0.550) and height at flowering (0.313) as traits with direct effects on grain yield, making them suitable for indirect selection. Overall, each germplasm source exhibited unique strengths and weaknesses. Ghanaian genotypes excelled in grain yield, while USA genotypes demonstrated early flowering and maturity. These findings can guide breeders in developing high-performing soybean varieties by leveraging desirable traits from each source