Genetic variability in soybean (<i>Glycine max</i> L.) for low soil phosphorus tolerance

Abstract

Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) conditions provides an understanding of the genetic potential of the genotypes to improve the crop for low P tolerance. The study was designed objectively to estimate the extent of genetic variability of soybean genotypes for low P tolerance. Thirty six soybean genotypes that were introduced from various sources were grown in simple lattice design with three replications at three locations in Western Ethiopia characterized by P-deficient-acidic soils. It was revealed that weight of 100 seeds; plant height, root and biomass fresh weight exhibited relatively high heritability and genetic advance on low P soils. Principal component analysis also revealed that the first five principal components (PCs) accounted for more than 85% of the total variation. The first principal component that contributed for 37.7% of the total variation was influenced by root fresh weight, tap root length, root volume, fresh biomass weight, days to maturity and days to flowering in the order of importance; indicating the significance of these traits for low P tolerance screening. Cluster analysis grouped the genotypes into four clusters. Observation of large variation and relatively high heritability indicates that selection would be effective to improve soybean varieties for performance on P stressed soils and identify low P tolerant varieties that helps smallholder farmers optimize soybean productivity on P deficient soils.