Assessment of Genetic Variability, Correlation and Path Analysis for Yield and Yield Contributing Traits in Onion (Allium cepa L.) Genotypes

Abstract

In recent years, the introduction of new onion genotypes and changing climatic conditions have necessitated a re-evaluation of genetic parameters to identify stable and high-yielding genotypes. Hence, there is a need to generate updated and location-specific information to support effective selection strategies in onion breeding programs. The present study aimed to estimate genetic variability and correlation and path coefficient analysis among twenty-eight onion genotypes for fifteen traits, including bulb yield and its contributing characters. These genotypes were evaluated in a Randomised Block Design with three replications during the Rabi season of 2021-22 at SKN College of Agriculture, Jobner. The analysis of variance indicated considerable variability for all fifteen characters. High to moderate GCV and PCV were observed for bolting, neck thickness, total yield per hectare, and average bulb weight. Most traits exhibited high heritability (47.1–96.2%), with high genetic advance as a percentage of mean for bolting, neck thickness, total yield, and average bulb weight, indicating the role of additive gene action. Character association results indicated that, at both phenotypic and genotypic levels, yield was positively associated with plant height, bulb volume, polar diameter, polar to equatorial diameter ratio, number of scales, average bulb weight, dry bulb weight, and total chlorophyll content. Path coefficient analysis showed a positive direct effect for the polar to equatorial diameter ratio, equatorial diameter, bulb volume, average bulb weight, and total chlorophyll content. Consequently, these traits are considered important contributors to the yield potential of onions. Therefore, it is recommended that these traits be prioritised in selection programs for improving bulb yield in onion crops.