Studies on genetic diversity in cucumber (Cucumis sativus L.)
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Date
2019
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Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur (Bihar)
Abstract
The present study was carried out at Vegetable Research farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar during Rainy Season 2018 using twenty one cucumber genotypes including the check, Swarna Ageti in Randomized Block Design with three replications. The observations were recorded on fourteen putative characters that include both qualitative and quantitative indicate namely, vine length, node number bearing first female flower, number of primary branches, days to first flowering, days to first harvesting, harvest duration, number of fruits per plant, shelf-life, TSS, seeds per fruit, fruit length, fruit diameter, fruit weight, fruit yield per plant. The different statistical parameters used for interpretation of data were Analysis of Variance, Genotypic and Phenotypic Variance, Genotypic and Phenotypic coefficient of Variance, Heritability, Genetic Advance, Correlation Coefficient Analysis, Path Coefficient Analysis and Genetic Diversity to study nature and magnitude of variability and diversity.
Analysis of variance revealed highly significant difference among twenty one genotypes of cucumber for all the fourteen characters from the variability studies. High estimates of PCV were observed for traits node number of first female flower, number of fruits per plant, vine length, fruit weight and fruit diameter whereas moderate GCV and PCV were recorded for shelf life, fruit length and TSS. In present set of materials high heritability with high genetic advance as per cent of mean was recorded for TSS, shelf life, node number of first female flower, fruit length and fruit diameter indicating preponderance of additive gene effect, which will facilitate
selection in early segregating generation. Traits like fruit weight, fruit diameter, fruit length, shelf life, number of seeds per fruit, number of fruits per plant and vine length showed significant positive correlation with fruit yield per plant and have positive direct effect at phenotypic level indicating the importance of these characters for further yield improvement.
Path analysis revealed traits like fruit weight, number of fruits per plant had positive direct effect as well indirect effect on fruit yield per plant at genotypic level and at phenotypic level.
Twenty one genotypes of cucumber were grouped into 5 clusters using Tocher‟s clustering method. Cluster III had maximum five genotypes, cluster I, II, IV and V each had four genotypes. Highest inter cluster distance was observed between cluster IV and cluster V followed by between cluster I and cluster V. Highest intra cluster distance was observed in cluster III followed by cluster I. Cluster IV showed higher mean performance for most of the yield attributing characters therefore, selection of parents from this cluster would be effective. Fruit weight, TSS, node number of first female flower and shelf life were major characters contributing towards genetic divergence. This shows that variability in the genotypes is only due to these characters which will offer a good scope for improvement of yield through rational selection of parental genotypes. Based on the result of all major parameter including qualitative and quantitative indices under present investigation, genotype Swarna Ageti, RCS 10 and RCS 18 appeared to the outstanding performs.
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