Genetic variability studies for yield and yield contributing traits in onion (Allium cepa L.)

Abstract

The onion (Allium cepa L.) bulb productivity is influenced by genotypes and seasonal environmental conditions. The selection of diverse genotypes with high variability is highly desirable, along with the extent of heritability and genetic advance of genotypes for wide adoption and cultivation. The present investigation was carried out by collecting genotypes from the onion growers. The results revealed that the variance of onion genotypes characters ranged from 2.87 to 43.56% for the genotypic coefficient of variation, 3.65 to 46.24% for the phenotypic coefficient of variation. Traits with higher genotypic coefficients of variation and phenotypic coefficients of variation indicated the existence of variation of traits among genotypes and lines. Heritability ranged from 24.72 to 96.85% and genetic advance mean ranged from 2.94 to 84.55%. Higher heritability and genetic advance mean to indicate the presence of additive gene action, thereby indicating that simple mass selection would be more reliable to improve traits in onion. The degree of association, the genotypic correlation was greater than the phenotypic correlation among onion genotypes. The yield was highly significant and was, correlated with growth and yield attributing traits among genotypes. Plot yield was influenced by direct and indirect positive, and negative, effects of growth, quality and yield attributing traits. Direct mass selection of desirable traits would be effective for bulb yield improvement in onion.