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20131
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Subject: Horticulture × Author: Daljinder Singh × End date: 2018 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF GERMPLASM AND F1 HYBRIDS.
    (PAU Ludhiana, 2013) Daljinder Singh; M. I. S, . Gill
    The present investigation entitled “Morphological and molecular characterization of guava (Psidium guajava L.) germplasm and F1 hybrids” was conducted during years 2010 to 2013 at P.A.U., Ludhiana and Regional Fruit Research Station, Bahadurgarh. Thirty five guava genotypes grafted on seedling rootstocks were evaluated for tree, vegetative, reproductive, fruit and seed characters based on UPOV descriptors. Statistically significant difference for all the traits was observed among tested genotypes. Among components of genetic variation, phenotypic and genotypic coefficient of variation for different traits ranged from 7.26 and 6.95 to 35.00 and 33.11 %, respectively. Divergence analysis based on D2 statistic grouped the tested genotypes into six clusters with variable number of genotypes in each cluster, indicating the presence of genetic diversity in them. Cluster I, cluster IV, cluster V and cluster VI showed intra cluster distance of 55.12, 55.40, 50.70 and 61.84 respectively, indicating sufficient dissimilarity among genotypes for morphological features. Molecular characterization using 80 SSR primer pairs was done enabling cluster analysis of 43 guava genotypes. Among the primers, 78 markers amplified 258 alleles across the 43 genotypes with an average of 3.25 alleles per locus. The highest number of seven alleles per locus was amplified by mPgCIR 32, followed by six alleles per locus by mPgCIR98. The power of discrimination was found to be least (0.00) for markers mPgCIR251 and mPgCIR 414 and highest (0.84) for markers mPgCIR137. Values of expected heterozygosity ranged from 0.00 in monomorphic locus (mPgCIR251 and 414) to maximum 0.79 for locus mPgCIR32, with an average 0.47 expected heterozygosity. Estimated genetic dissimilarity coefficient ranged from minimum 0.020 (between genotypes 14-10 and 12-11) to 0.590 (between One Kg and Portugal) with an average dissimilarity of 0.322 across all the genotypes. Cluster analysis on the basis of molecular analysis classified the guava genotypes into two major groups having 3 and 40 genotypes each. The dendrogram generated using SSR markers along with the phenotypic data will be useful for choosing the diverse parents for further guava breeding programmes. A total of nine F1 hybrids were generated and vegetative parameters were recorded in different hybrids to distinguish them, as well as SSR markers were also used to confirm the parentage of these hybrids.