Studies on Genetic Divergence and Molecular Characterization in Cucumber (Cucumis Sativus L.)

Abstract

The present study was conducted during zaid, 2019 at Horticultural Research Center of Sardar Vallabhbhai Patel University of Agriculture and Technology, Modipuram, Meerut (250110) Uttar Pradesh. The experiment was laid out in Randomized Block Design (RBD) and using 20 genotypes of cucumber with nine Quantitative traits were considered to obtain information on the nature and magnitude of genetic variability, degree of association among different yield contributing traits with yield and revealed traits and the degree of genetic divergence and molecular analysis at the morphological level. Observation was recorded on various characters viz. vine length (cm), number of primary branches per plant, days to 50% flowering, days to first fruit harvest, number of fruits per plant, fruit length (cm), fruit diameter (cm), average fruit weight, fruit yield(q/ha). ANOVA showed highly significant variation for all traits indicating greater variability in the germplasm. High genotypic and phenotypic coefficient of variation was observed in the number of primary branches (30.87%), which indicates that high degree of variability in these characters. High heritability accompanied with high expected genetic advance expressed as percent of mean were recorded for average fruit weight (59.01%). Days to 50% flowering exhibited a highly significant positive correlation association with fruit length (0.701 & 0.602) for both genotypic and phenotypic levels. The highly genotypic path coefficient analysis showed a positive indirect effect on average fruit weight (0.269) and days to first fruit harvest (0.420) observed direct positive effect at the phenotypic level. The number of fruits per plant was maximum contributed to divergence (17.38%) and the minimum was contributed to divergence by average fruit weight (4.87%). Mahalanobis (D2) static revealed considerable genetic diversity among the genotypes. Genotypes were grouped into Ⅴ clusters. Cluster Ⅱ and Ⅴ both have maximum 6 genotypes. In the present study, the minimum inter-cluster distance (1.673) in cluster Ⅳ and maximum was found in cluster Ⅲ (2.168). Maximum intra cluster distance (4.954) were found between cluster Ⅰ and cluster Ⅳ and the minimum was found (2.692) between cluster Ⅲ and cluster Ⅳ. Molecular marker analysis revealed that 10 RAPD primers produce 32 alleles. Average PIC value for RAPD 0.615. The Average resolving power was 3.48 for RAPD.