Genetic Divergence Studies in Cucumber (Cucumis sativus L.)
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Date
2023
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SKUAST Kashmir
Abstract
The present investigation entitled “Genetic Divergence Studies in Cucumber (Cucumis sativus L.)” was undertaken to obtain information on variability, character association and genetic divergence among thirty-five (35) genotypes of cucumber with respect to various traits. A set of thirty-five genotypes of cucumber were evaluated in a Randomized Block Design replicated thrice during the Kharif season, 2021 at Vegetable Experimental Farm of Division of Vegetable Science, SKUAST-Kashmir, Shalimar, Srinagar. The data was recorded from five randomly selected plants for each genotype in all the replications for twenty characters viz; days to first male flowering; days to first female flowering; days to 50% flowering; days to first fruit harvest; fruit length (cm); fruit diameter (cm); average fruit weight (g); number of fruits per plant; average fruit yield per plant (kg/plant); fruit yield per hectare (q/ha); days to last fruit harvest; vine length (m); number of primary branches; inter nodal length (cm); number of nodes per vine; 1000 seed weight (g); moisture content (%); total soluble solids (°Brix); pericarp thickness (mm) and ascorbic acid content (mg/100g). The present investigation revealed that among 35 genotypes of cucumber (based on mean performance) three genotypes viz. Pusa Barkha, Dharwad green and Sweet delight had substantially higher yield and performed better for other desirable traits as compared to Japanese Long Green (Check). It is also concluded that analysis of variance showed significant variation among different genotypes for all characters studied. Moderate GCV and PCV was recorded for number of primary branches per plant, fruit yield per plant, vine length (cm) and inter nodal lengthin comparison to other characters indicating the presence of high amount of genetic variability for these characters. high heritability coupled with high genetic advance as percent of mean was observed for fruit diameter (cm), vine length (cm), fruit yield per plant (Kg/plant), no. of fruits per plant and number of primary branches per plant. This indicates closeness of respective σ2p and σ2g value thereby low environmental effect on expression of these characters. Such values may be attributed to the additive gene effects and direct selection for these traits would be fruitful. Thus, phenotypic selection may be effective for these characters. Fruit yield per plant exhibited highly significant and positive correlation with fruit length (cm), fruit diameter (cm), average fruit weight (g), number of fruits per plant, vine length (cm) and number of primary branches per plant. Fruit yield per plant showed significant negative correlation with days to first male flower, days to first female flower, days to 50% flowering, days to first fruit harvest and days to last fruit harvest at phenotypic level. Path coefficient analysis revealed that maximum positive direct effect on fruit yield was observed by fruit length, inter nodal length, number of fruits per plant, vine length (cm), days to first female flowering and number of nodes per vine at both genotypic and phenotypic level. Based on Mahalanobis’ D2 statistics 35 genotypes of cucumber were grouped into six clusters. Maximum numbers of 16 genotypes were included in cluster 1 followed by cluster 3 with 12 genotypes, cluster 2 with 4 genotypes, cluster 4, cluster 5 and cluster 6 with only single genotypes in each cluster. The maximum contribution towards total divergence was observed by average fruit weight followed by fruit yield per plant (kg/plant), number of fruits per plant, fruit diameter (cm), vine length (cm), fruit yield per hectare (q/ha), days to first male flowering, number of nodes per vine, ascorbic acid (mg/100g), inter nodal length (cm), number of primary branches per plant, 1000-seed weight (g) contributed maximum towards total divergence. It can be concluded that the crosses between parents from cluster 2nd and 4th, 2nd and 3rd and 1st and 2nd are likely to exhibit high heterosis with desired traits.
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Keywords
GCV, PCV, Heritability, Genetic Advance, Correlation coefficient analysis, Path analysis, D2 statistics, Vegetable Science