GENETIC ANALYSIS OF AMYLOSE CONTENT IN RICE (Oryza sativa L.)

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dc.contributor.advisorSATYANARAYANA RAO, V
dc.contributor.authorYUGANDHAR PANGA, RAVI
dc.date.accessioned2020-02-26T09:29:57Z
dc.date.available2020-02-26T09:29:57Z
dc.date.issued2019
dc.descriptionD5891en_US
dc.description.abstractRice is one of the three most important grain crops in the world and contributing majorly to the food needs across the world. The role of rice crop in the present and the future global food security is unavoidable. In the past, increasing the yield potential was only the priority in research across the globe to meet the food demand for the increasing population. At present, the living conditions of the people are being gradually improved and the consumers are demanding for superior quality rice, especially for cooking and eating quality. Amylose content (AC), gel consistency (GC) and gelatinization temperature (GT) are the major eating and cooking quality traits which are primarily influenced by the starch. Among them, amylose content is prime important as it determines the texture of cooked rice. A better understanding of the factors which are influencing the overall grain quality of rice offer the scope for the development of new breeding and selection strategies to mingle high yield with superior quality. Present investigation was conducted to identify the genomic regions governing the amylose content and gel consistency via molecular breeding approaches and also to examine the genetics of amylose content in rice. The results of ANOVA revealed significant differences among all the genotypes for 20 agro-morphological and quality traits studied. Highly significant genotypic effects were found for all the studied traits. The results suggested that the genotypes had high diversity for all the characters. The distribution of phenotypic values of all the traits was showing continuous across genotypes which clearly indicated the quantitative nature of genetic variation. The total genotypes were grouped into three clusters based on ward minimum variance method to identify diversity among the germplasm lines. There were 24 genotypes comprised in cluster I, 26 genotypes in cluster II and 51 genotypes in cluster III. xiv After evaluation of germplasm lines, six crosses viz., SR11 X IR64, SR10 X IR64, SR9 X swarna, SR7 X swarna, SR11 X Jaya and SR14 X Jaya were made by using SR2, SR7, SR9, SR10, SR11, SR14, IR64, Swarna and Jaya genotypes with diverse amylose contents. The F1 seed of all the crosses was harvested and evaluated for amylose content and advanced to the next generation. Among them, one cross, SR11 X Jaya was used developed F2:3 mapping population which was also used to study the inheritance pattern of amylose content. The population could essentially be classified into two distinct categories i.e. 3-15% and 16-30% and fitted into of 1:3 ratio which confirmed the role of single major gene governing the amylose content. The presence of a few individuals having higher or lower levels of amylose content as compared to parents indicated the role of polygenes or modifiers. F1seeds of all the crosses were harvested and were selfed during rabi, 2015-16 to develop F2 population and further advanced by single seed descent method. 439 F2 plants of the selected cross was used as mapping population to map the genes governing amylose content and gel consistency. Parental polymorphism between SR11 and Jaya was studied during rabi, 2015-16 by using 1173 SSR markers. Among them, 112 markers showed polymorphism between the two parents (SR11 and Jaya), used for genotyping of F2:3 mapping population. The phenotyping and genotyping for amylose content and gel consistency in the mapping population of the selected cross, SR11 X Jaya was done during kharif, 2016. Genotyping was done using 112 SSR markers which showed polymorphism between the two parents. The frequency distributions of amylose content and gel consistency showed bimodal distribution. A linkage map consisting of twelve linkage groups was constructed by using 112 polymorphic SSR marker loci. The linkage groups were assigned to different chromosomes based on presence of SSR markers in the respective groups in the mapping population. The association between the markers with amylose content and gel consistency in the population was studied using linkage analysis during rabi, 2016-17. The method of composite interval mapping used to identify the genomic regions governing the amylose content and gel consistency. Three QTLs on chromosome 6 viz., qAC-6-1 qAC6-2 and qAC-6-3 in the marker interval of JGT6_18.1 - RM190, RM190 - RM587 and RM587-RM204 were identified for amylose content and three QTLs viz., qGC-6-1, qGC-6-2 and qGC-6-3 were identified in the same location for gel consistency. The markers which are linked to the QTLs have stronger LOD score and phenotypic variance, these can be used for marker assisted selection to develop the rice varieties with desirable amylose content and gel consistency. The marker RM190 showed highest LOD score as well as highest phenotypic variance of amylose content was used to validate the QTLs of amylose content in 26 germplasm lines with different amylose contents. The marker RM190 could efficiently be able to differentiate the rice varieties with different levels (high and low) of amylose contents. Hence, it could be a useful component of the breeding programmes to breed the rice varieties with desirable amylose content. This finding has provided clues to resolving the molecular bases of AC and GC in future studies. The results also have direct implications for the quality improvement of rice varieties with desirable AC and GCen_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810143611
dc.keywordsGENETIC ANALYSIS, AMYLOSE CONTENT, RICEen_US
dc.language.isoen_USen_US
dc.pages209en_US
dc.publisherACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTURen_US
dc.research.problemGENETIC ANALYSIS OF AMYLOSE CONTENT IN RICE (Oryza sativa L.)en_US
dc.subGenetics and Plant Breedingen_US
dc.subjectnullen_US
dc.themeGENETIC ANALYSIS OF AMYLOSE CONTENT IN RICE (Oryza sativa L.)en_US
dc.these.typePh.Den_US
dc.titleGENETIC ANALYSIS OF AMYLOSE CONTENT IN RICE (Oryza sativa L.)en_US
dc.typeThesisen_US
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