R. C. JAGADEESHCHITTAPUR, REKHA.GASTI, V. D.PATIL, BAPURAYAGOUDA.D. S. AMBIKASHIVALEELA2023-10-092023-10-092021UHS18PGM1053https://krishikosh.egranth.ac.in/handle/1/5810198591The present investigation was carried out with forty local cucumber collections, which were collected from different regions of Karnataka and evaluated in randomized block design to study the variability, diversity, character association, path analysis, heterosis and molecular diversity at the Department of Biotechnology and Crop Improvement, COH, Bagalkot during 2019-20. Analysis of variance revealed that significant difference observed among ecotypes for all characters except fruit diameter. High PCV, GCV, heritability and high genetic advance over mean were recorded for parameters like vine length at 30 days, number of branches per vine, sex ratio, node number at first female flower appearance, number of fruits per plant, yield per plant, pulp thickness, yield per plant was positively and significantly associated with plant height, number of branches per plant, node at first female flower appears, number of male flowers, number of female flowers, sex ratio, number of fruits per plant, individual fruit weight and fruit length. Path analysis revealed that, highest positive direct effects on total yield per plant was shown by vine length, node at first female flower appears, average fruit weight, number of fruits per plant, individual fruit weight, and fruit length. Genetic divergence analysis using Mahalanobis‟s D2 statistic grouped forty local collections of cucumber into three clusters, of which five local genotypes of cluster II showed maximum intra-cluster distance. The inter cluster average D2 value was maximum between cluster II and III. Per se value of majority of the F1 s were higher than the parents. A high magnitude of heterosis was exhibited over mid parent and better parent. Considering the overall performance in respect of fruit yield per vine, most promising hybrids viz., hybrid-2 (UHSCS-1 x UHSCS-3), hybrid-3 (UHSCS-13 x UHSCS-1) and hybrid-4 (UHSCS-17 x UHSCS-21) exhibited high heterotic effects. The local genotypes UHSCS56, UHSCS-79 was found superior for both growth and yield parameters. These hybrids can be used for further evaluation. SSR markers are co-dominant and highly reproducible which can be used in molecular characterization comparison with other molecular markers. Molecular characterization of forty local collections of cucumber was carried out by using 19 SSR markers. Dendrogram revealed three major clusters. For confirmation of hybridity through SSR markers to analyze the purity of hybrids.EnglishThesis