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|Title:||GENETIC STUDIES IN SNOWBALL CAULIFLOWER (Brassica oleracea var. botrytis L.) USING CMS AND DH LINES|
|Publisher:||DIVISION OF VEGETABLE SCIENCE ICAR- INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI|
|Abstract:||The heterosis has been proved miraculous tool for the development of F1 hybrids with better nutritional traits and high productivity in Brassica vegetables. In this context the present investigation was undertaken using 20 genetically diverse OguraCMS lines and 6 doubled haploid male fertile inbred to estimate combining ability, heterosis and nature of gene action for different agronomic and antioxidant traits. The characterization of parental lines was carried out using microsatellite (genomic-SSR and EST-SSR), morphological and biochemical markers.The variation in mitochondrial genome of Ogura cytoplasm based 76 male sterile lines was analyzed using mitochondrial (genome specific and mt-SSR) markers. The parental CMS lines and DH testers were crossed to develop 120 F1 hybrids in line × tester mating design. The resulting 120 test cross progenies plus 26 parents along with 4 standard checks were evaluated in 10 × 15 alpha lattice design with three replications at Baragram Experimental Farm of ICAR-IARI, Regional Station, Katrain, Himachal Pradesh. The results obtained revealed that all the studied traits were found to be under the genetic control of both additive and non-additive gene effects. The less than unity value of σ 2A/D and σ2 gca/σ2 sca ratios indicated the preponderance of non-additive gene action in the genetic control of majority of studied traits. The CMS lines Ogu118-6A, Ogu33A and Ogu34-1A were good combiner for developing hybrids with early maturity. The CMS lines Ogu122-5A, Ogu33A, OguKt-2-6A, Ogu1-6A and Ogu126-1A could be used as female parent for developing high yielding hybrids. The CMA lines CMS lines Ogu122-5A and Ogu115-33A were found good combiner for majority of antioxidant traits. The statistical analysis revealed that most of the heterotic hybrids were associated with high positive SCA effects. The crosses Ogu34-1A × 53-1, Ogu2A × DH-53-1, Ogu2A × DH-53-9 and Ogu33A × DH-53-9 can be recommended for further evaluation trial for developing hybrids with early maturity. The crosses, Ogu126-1A × DH-18-8-3, Ogu122-5A × DH-53-10 and Ogu307-33A × DH-18-8-3,were found best heterotic crosses for yield and its contributing traits. The heterotic crosses Ogu125-8A × DH-53-1, Ogu125-8A × DH-53-6 and Ogu34-1A × DH-53-9 found best for accumulation of ascorbic acid content. The molecular analysis revealed that, among 350 microsatellite markers, 87 primers showed high polymorphism among the parental lines. The PIC content ranged from 0.24 to 0.80 and genetic distance varied from 0.44 to 0.98. The significant association of genetic distance based on polymorphic genomicSSR and EST-SSRs with heterosis for commercial traits indicated the utility of genetic distances in prediction of heterosis in cauliflower. The F1 hybrids with better combining ability and better per se performance could be useful in accumulation of favorable allele for enhancing antioxidant traits and total marketable yield in cauliflower. The ratio of petal length to petal width was >2 in majority of the CMS lines indicating the great reduction in petal width relative to petal length with the Ogura cytoplasm. The significant differences were found in the CMS lines with respect to their male fertile counterparts (B lines) regarding floral traits. The introgression of Ogura cytoplasm resulted in reduction of flower size, stamen length and style length in CMS (A) lines as compared to their respective maintainer (B) lines carrying normal cytoplasm. The highest quantity of nectar was found in the CMS line Ogu1-8A followed by Ogu308-6A and Ogu2-6A. The results revealed that in majority of the cases the relative position of stamen was reduced to lower level as compared to style. In all the CMS lines under study, the test weight of > 3 g was recorded. The PCR-amplification of all the 76 CMS lines with respect to mitochondrial markers revealed that all the CMS lines were derived from the Ogura cybrid cytoplasm, although there are differences among the CMS lines with respect to nucleotide sequences. The sequence analysis depicted SNPs, insertions, deletions among Ogura cybrid cytoplasm based CMS lines of cauliflower resulting in mitochondrial genome variation in Ogura CMS system. Thus, the mitochondria specific markers can be effectively utilized for identification of CMS types, assessment of cytoplasmic diversity and variability in mitochondrial genome of different male sterility systems in Brassica oleracea vegetables and enhancing heterosis breeding programmes based on cytoplasmic male sterility. Key Words: CMS, Doubled Haploid, Brassica oleracea, Heterosis, Mitochondria, Genetics|
|Theme:||GENETIC STUDIES IN SNOWBALL CAULIFLOWER (Brassica oleracea var. botrytis L.) USING CMS AND DH LINES|
|Appears in Collections:||Theses|
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