Molecular characterization of parental lines and genetical studies in crosses of cucumber (Cucumis sativus L.)
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Date
2014-08
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Abstract
The present investigation was carried out at Vegetable Research Centre (VRC) and Department of Vegetable Science, G.B.P.U.A & T, Pantnagar, Uttarakhand during 2011-2013. The objectives of the study were to determine the variability, heritability, gene action, extent of heterosis, combining ability and molecular diversity using SDS-PAGE and ISSR marker of gynoecious and monecious genotypes of cucumber. Thirty crosses were produced in a line x tester mating design with three genotypes as female parents and ten genotypes as male parents.
Analysis of variance revealed highly significant variances among the genotypes for twelve characters which indicated adequate variability to carry out genetical studies. Most of the genotypes were early in flowering. A valuable range of days to first harvest varied from 38.00 to 70.33 whereas, yield q/ha was found to vary from 99.73 to 378.20. PCV was slightly higher than GCV for all the traits. Broad sense heritability (hb2) value was observed high for all the traits. All the crosses were significant over better parent and standard variety for days to first female flower and days to first harvest. Highest heterobeltiosis was observed in Pgyn-4 x US-832, Pgyn-5 x Pant Khira-1 and Pgyn-5 x Pant Khira-1 (31.79%) for number of fruit/vine, fruit yield (q/ha) and average fruit weight (g), respectively. Among the lines genotype Pgyn-1 was identified as the best general combiner days to first male flower, days to first female flower, node number to first male flower and inter-nodal length. Pgyn-4 was found good combiner for days to first harvest, fruit length, fruit diameter, number of fruit per plant and vine length whereas, the testers US-832 and Pant Khira-1 were good general combiner for most of the yield contributing traits. The cross Pgyn-5 x US-832 exhibited high SCA effect in desirable direction for days to first male flower, days to first harvest, inter-nodal length, days to first female flower. Cross Pgyn-4 x US-832 was found good specific combiner for fruit length, vine length, number of fruit per plant. The SDS-PAGE analysis of seed protein differentiated Pgyn-1 and Pgyn-4 rest of the other monoecious lines. ISSR analysis amplified a total 52 loci with 50-100% polymorphism. Similarity among germplasm varied from 22-80%. The primer UBC-808 showed a unique band of 650 bp with the genotype PCUC-35 and Pgyn-4 with160 bp.
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Thesis-PhD
Keywords
molecular biology, characterization, hybridization, genetic analysis, cucumbers, cucumis sativus, vegetables, crosses, SDS-PAGE, markers, genotypes, heterosis