Selection of crops is preceded by multi-locational testing in plant breeding; however, it becomes difficult for
breeders to determine which genotypes should be selected in the presence of genotype by environment (GEI). Six
genotypes of soybean (
Glycine max
(L.) Merr.) were evaluated at ten locations in Nigeria for grain yield and
stability. The analysis of variance revealed significant (P ≤0.05) GEI effect. Mean grain yield of the soybean
genotypes ranged from 1148 kg ha
-1 for genotype M351 to 1584 kg ha
-1 for TGx 1448-2E. Ilorin in the southern
guinea savanna of Nigeria was the most variable with high interaction principal component axes (IPCA); while
Bauch in the northern guinea savanna was identified as more stable location in evaluating the soybean genotype.
Mega-environments and the best yielding soybean genotypes in each mega-environment were revealed by the
GGE biplot analysis. Furthermore, TGx 1448-2E and TGx 1440-1E, were established as the most promising, and
stable genotypes across the test locations. Stability model of GGE biplot was superior, effective and informative
in mega-environment analysis compared to AMMI analysis.