Boosting soybean adaptation in Africa through multi-trait selection in multi-environment trials
Yasmim Isabel Retore, Bruno Figueiró Fregonezi, João Paulo Silva Pavan, Godfree Chigeza, Erica Pontes Leles, Michelle F. Santos, Peter Goldsmith, Brian Diers, Mauricio dos Santos Araújo and José Baldin Pinheiro
Abstract: Soybean breeding in Africa is constrained by environmental heterogeneity and strong genotype-by-environment (G×E) interaction, which limits the identification of high-performing and stable genotypes. We evaluated 145 soybean genotypes across 24 environments in seven African countries for grain yield (GY), number of days to maturity (NDM), 100-grain weight (W100), oil content (OIL), and protein content (PROT). Likelihood ratio tests indicated significant genotype, environment, and G×E effects for all traits. GY ranged from 1.404 to 3.391 kg ha⁻¹, with variation in maturity and grain composition associated with altitude and cropping season. Genetic correlations revealed important trade-offs, including positive associations among GY, NDM, and W100, and antagonism between OIL and PROT. Multi-trait selection with 10% intensity identified 14 genotypes closest to the ideotype, with expected gains of 15.7% in GY and favorable responses in the other traits. These findings demonstrate the effectiveness of multi-trait, multi-environment strategies for soybean improvement in Africa.