Thumbnail Image

Thesis

Browse

20111
Reset filters
Subject: Plant Breeding × Author: Arora, Naveen × End date: 2018 × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Assessment of Genetic Diversity in Sugarcane
    (Punjab Agricultural University, Ludhiana, 2011) Arora, Naveen; Gill, Ranvir Singh
    In the present studies a set of seventy two genotypes including five checks was used to study the variability, heritability, genetic advance and genetic divergence based on Mahalanobis D2 analysis. The test material belongs to twenty four diverse cross combinations (six biparental crosses and eighteen general crosses). The significant levels of variability were observed among the genotypes for all the traits of agronomic interest viz. cane yield, commercial cane sugar tons per hectare (CCS t/ha), germination (percent), number of tillers (000/ha), number of millable canes (000/ha) single cane weight (kg), number of internodes, cane girth (cm), cane length (cm), total soluble solids at 240 DAP (TSS %), POL% juice (240 DAP), purity % (240DAP), commercial cane sugar percent juice at 240 DAP (CCS %), total soluble solids at 300 DAP (TSS %), pol percent juice (300 DAP), purity coefficient (300 DAP), commercial cane sugar percent juice at 300 dap (CCS %), ethanol potential liters per tons (EP). The genotypes S1032/07, S782/07, S863/07, S643/07, S196/07 and S209/07 were found promising genotypes on the basis of their mean performance for different traits. The estimates of phenotypic coefficient of variability, genotypic coefficient of variability, heritability, and genetic advance indicated that emphasis should be given on traits like cane yield (t/ha), commercial cane yield (t/ha), number of tillers (000/ha), number of millable canes (000/ha), single cane weight (kg) and commercial cane sugar (%) at the time of selection for achieving desired improvements in crop breeding programs. The divergence analysis based on Mahalanobis D2 grouped seventy two genotypes into nine divergent clusters. The intracluster distances were smaller as compared to the intercluster distances indicating that genotypes with in a cluster are sufficiently divergent from the genotypes of other clusters. The clusters differed with respect to cluster means for different agronomic traits under study. Cluster I & II were characterized by high cane yield (t/ha), commercial cane sugar (t/ha) and single cane weight (kg). Cluster II & IV had highest number of tillers and number of millable canes (000/ha). Cluster V, VII and IX were characterized by better quality. Only few traits viz. cane yield (t/ha), number of tillers (000/ha), number of millable canes (000/ha) and cane length (cm) contributed towards the genetic divergence. From the same set of material a set of fifty two visually chosen agronomically superior genotypes were analyzed for genetic diversity at molecular level. A total of eighty four alleles/bands were scored with a set of thirty one simple sequence repeats markers indicating 2.64 alleles per locus. Polymorphism information content (PIC) value was found to range from 0.17 to 0.74 with a mean value of 0.54 indicating a moderate range of diversity in the test material. On the basis of DARwin’s Dice dissimilarity coefficient the fifty two genotypes were grouped into seven distinct clusters. Genotypes CoJ 85 and S877/07 were the most divergent. The clustering pattern based on Mahalanobis D2 analysis and SSR marker based analysis indicated that parentage did not contributed towards the clustering pattern. Also the distribution of genotypes into different clusters based on the two approaches was different. The material under study indicated a good level of variability and genetic diversity. The potential of SSR markers in diversity analysis is also demonstrated.