Genetic variability, character association and path analysis for different traits in white onion genotypes under short day condition

Abstract

Aim: To estimate the nature and magnitude of genetic diversity of white onion genotypes. Methodology: The experiment was carried out for two consecutive years (2018-19 and 2019-20) at ICAR-DOGR, Pune. Thirty-five genotypes of white onion identified as low and high TSS genotypes were used to study their genetic variability, character association, path analysis and genetic diversity for different morphological and biochemical traits. Results: Significant differences were observed among all the genotypes. High expression of GCV over PCV was recorded for percentage double indicating lesser influence of environment. The broad sense heritability values were higher (60%) for all the characters under study ranging from 62.10% in days to 75% neck fall to 98.38% in total sugar. Plant height, leaf length, polar diameter and equatorial diameter exhibited significant positive correlation with total bulb yield. Genotypic path analysis showed that leaf length (cm) had maximum positive direct effect on total bulb yield followed by equatorial diameter, total sugar and total pyruvic acid of bulb. Interpretation: Considering the cluster distance and cluster means for bulb yield quality traits and morphometric traits three genotypes viz., Bhima Shweta, Bhima Shubra from cluster III and WHTB-7G-GT-15-SC-M-7 Small Bulb from cluster II were good candidates for utilization in breeding programs. Genotypes belonging to cluster I WHTS-4D-GT-18-MC-M-7 (18.49%), WHT-2B-GT-18-SC-M-7 (18.51%), WHTB-3C-GT-18-MC-M-7 (18.27%) and WHT-12L-HT-15-REJECT-M-7 (18.02%) can be utilized as high TSS donors in quality improvement programmes. This study also indicated that, direct selection of leaf length and equatorial diameter will be beneficial in framing yield improvement programme.