Genetic variability, heritability and genetic advance of soybean (Glycine max) genotypes based on yield and yield-related traits

Abstract

The success of breeding programme relies on the variability present in the breeding material. Selection is also effective when there is significant amount of genetic variability among the individuals in a population. The study aimed at assessing genetic variability, heritability and genetic advance among yield and yield components of soybean genotypes. Eighty-two genotypes maintained at the Agricultural Research Council-Grain Crops were planted in an alpha lattice design, replicated twice in Potchefstroom and Brits in South Africa in 2017/18 growing season. Five plants per genotype were selected and yield and yield related traits were measured. Data were analysed through analysis of variance and genetic parameters were estimated. The results showed highly significant differences among the genotypes based on days to flowering, branch number per plant, hundred seed weight, pod weight per plant, pod length, seed number per plant, seed number per pod and grain yield. Heritability of yield and yield components were ranged from 5.9% to 100%. The most heritable traits were hundred seed weight (100 %), days to flowering (64.13 %) and seed number per pod (67.37%). The genotypic variance ranged from 0.3% to 33% while the phenotypic variation ranged from 1.5% to 44%. The phenotypic and genotypic coefficient of variations was high for grain yield, medium for days to flowering and lowest for hundred seed weight. The phenotypic coefficient of variations (PCV) was higher than genotypic coefficient of variation (GCV) for all characters indicating the influence of environmental factors. The expected genetic advance was high for most of the traits, medium for seed number per pod and hundred seed weight and low for pod number per plant. The expected genetic advance as percent of mean was variable and high for all traits. There was vast variation observed among the soybean genotypes evaluated based on the yield and yield related traits