Assessment of Genetic Variability in Soybean (Glycine max (L.) Merrill) Genotypes at Gondar, Ethiopia

Abstract

Identification and utilization of genetically diverse germplasm are the primary objectives of crop improvement. This study evaluated 81 soybean (Glycine max (L.) Merrill) genotypes in Metema and West Armachiho districts of Northwestern Ethiopia during 2019/2020 using a simple lattice design to assess phenotypic variability and propose effective selection strategies. Combined analysis of variance revealed significant differences (P ≤ 0.05) among genotypes, locations, and genotype × location interactions for most traits. Estimations of genetic variability, heritability, and expected genetic advance indicate significant genetic variability among the tested genotypes. Key traits exhibited high broad-sense heritability (h²b) and genetic advance as a percentage of the mean (GAM), including days to 50% flowering (94.84, 30.21), plant height (92.13, 38.63), branches per plant (80.89, 46.15), pods per plant (71.90, 46.22) and hundred seed weight (85.12, 21.93), suggesting significant potential for genetic improvement in these traits. Cluster analysis grouped the genotypes into six clusters, with Cluster I being the largest (63%), followed by Cluster III, which contained 11.11% of the genotypes. The maximum inter-cluster distance was between Clusters II and VI (D² = 154.64), indicating high genetic divergence suitable for hybridization. Principal component analysis attributed 77.98% of the total variation to the first four components, emphasizing traits critical for selection. In conclusion, the study demonstrated significant variability among the genotypes, which could be exploited in future soybean improvement programs.