Studies on genetic variability and divergence in onion (Allium cepa L.)

Abstract

A study on variability, heritability, genetic advance and genetic divergence between traits in fifty three diverse onion genotypes was carried out for bulb yield, yield attributing traits and quality parameters. The range of variation was maximum for average bulb weight followed by leaf area, total soluble solids and yield per plot. The genotypic coefficient of variation (GCV) was high for average bulb weight (16.09%) followed by yield per plot (13.06%), total soluble solids (11.94%), leaf area (11.75%) and leaf area index (11.75%). The phenotypic coefficient of variation (PCV) was high for average bulb weight (16.90%) followed by leaf area (16.41%), leaf area index (16.41%), yield per plot (13.70%) and total soluble solids (12.77%). Higher heritability estimates along with high genetic advance as per cent of mean (GAM) was observed for yield per plot followed by average bulb weight and total soluble solids. All fifty three genotypes were grouped into ten different clusters. The highest inter cluster distance was observed between cluster IV and X (204.78) and lowest between cluster I and V (35.56).Based on cluster means the important cluster was cluster IX for plant height, bulb neck thickness, number of rings cluster X for leaf area, leaf area index, average bulb weight, total soluble solids, bulb length and yield per plot cluster VIII for number of leaves cluster V for bulb diameter and cluster VII for bulb shape index. Accordingly, parents could be selected for hybridization. The highest intra cluster distance was observed between cluster VII (40.09). The high diversity found in the genotypes showed its great potential for improving qualitative as well as quantitative traits in onion.