Morphological characterization, divergence and disease reaction studies for improvement of mid-late and late maturity genotypes of cauliflower under North-Western Himalayas

Although numerous varieties have been recommended across different agro-climatic zones of Himachal Pradesh, however the information on high yielding genotypes with higher quality and disease resistance is lacking in this state. Diseases like black rot and stalk rot are the main obstacle preventing cauliflower production in this area. Therefore, in this investigation, thirty genotypes of cauliflower were evaluated for morphological characters based on DUS, horticultural traits, character associations, genetic divergence and disease reaction studies to identify superior genotypes for commercial cultivation. The experiment was designed in Randomized Complete Block Design (RCBD) with three replications. The genotypes were morphologically classified based on twenty-one DUS characters, further identifying genotypes for inclusion in breeding programmes or direct use as a cultivar. Mean performance of genotypes for various traits disclosed that Pusa Himjyoti recorded the highest marketable curd yield/hectare and genotypes Snowball Super, White Heart, UHF-CAU-1, Early Snowball, UHF-CAU-4, UHF-CAU-8 and KT-18 were determined to be statistically at par with Pusa Himjyoti. All these genotypes have white to snow white curd with self- blanching habit. High heritability along with moderate genetic advance as per cent of mean was observed for net curd weight confirming the occurrence of additive gene action. Correlation coefficient discovered that the number of leaves/plant, plant spread, curd polar diameter, curd equatorial diameter, curd size index, curd solidity, gross plant weight and net curd weight were found to be significantly and positively correlated with marketable curd weight. The maximum positive direct effect on marketable curd weight was contributed by curd equatorial diameter followed by curd polar diameter, net curd weight, curd solidity and number of leaves/plant. Thus, perfection in these traits will lead to higher yield in cauliflower. The D2 analysis grouped the genotypes into three clusters consists maximum genotypes in cluster II. Gross plant weight (32.00%), net curd weight (18.16%), plant height (8.33%) and marketable curd yield (8.21%) were identified as significant traits contributing to divergence. In case of disease reaction studies, no genotype was found resistant to stalk rot while, in black rot, only one genotype White Heart was found resistant whereas Snowball Super and PSBK-1 showed moderately resistant reaction.