Molecular mapping for low light intensity tolerance using the contrasting rice genotypes of Eastern India

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dc.contributor.advisorRai, Mayank
dc.contributor.authorDutta, Suvendhu Sekhar
dc.date.accessioned2023-01-27T06:51:56Z
dc.date.available2023-01-27T06:51:56Z
dc.date.issued2017-05
dc.description.abstractRice (Oryza sativa L.) is the most important cereal crop of the Eastern and North-Eastern India. Low light induced problems include high tiller mortality at vegetative stage, reduction in spikelet number, spikelet sterility and reduced dry matter production. A set of contrasting genotypes in the NEHR mini core set during kharif-2014 and a set of 110 rice genotypes from different parts of eastern India were screened for low light intensity tolerance during kharif-2015. Total grain yield, spikelet fertility, biological yield, number of effective panicles, specific leaf weight and chlorophyll content were found to be the key traits response to low light intensity (30 % less than normal). A panel of forty six genotypes made up of top twenty three tolerant and susceptible genotypes each, based on field screening in kharif-2015 along with previously reported checks (Swarnaprabha- tolerant and IR 8-suceptible) was used for mapping study. By using the online rice databases, a set of ninety eight genes previously reported for light response were identified, which was then narrowed down to twenty. Molecular markers (forty five HvSSRs and newly designed twenty eight gene based primers) were used for molecular mapping for low light intensity tolerance. Standardization of these seventy three primers in a set of eight contrasting genotypes led to identification of fifteen HvSSR and two gene based polymorphic (CAU-CG-ILA1-3 and CAU-CG-RK3) primers. These polymorphic primers were run on the mapping panel. Marker-trait association studies based on t test and regression analysis revealed seven HvSSR and one gene based markers associated with the key traits viz., HvSSR01-66, HvSSR02-54 and CAU-CG-ILA1-3 with grain yield, HvSSR02-52, HvSSR06-56, HvSSR06-69 and HvSSR09-45 with spikelet fertility and with biological yield HvSSR02-44, HvSSR02-52, HvSSR06-69, HvSSR09-45. Expression analysis for the genes used for mapping (LGD1, PNH1, ILA1, CAB2R and LP2) was performed on a panel of eight contrasting rice genotypes grown under normal light and low light intensity (75 % of ambient) at two time points (one hour and two days). Relative expression of the five selected genes in the leaf next to flag leaf showed that there was significant down regulation of transcripts after one hour of low light treatment insusceptible genotypes for genes LGD1 and PNH1, whereas the transcript levels were maintained in tolerant genotypes. Transcription was significantly down regulated and up regulated, respectively for ILA1 and LP2 genes specifically in tolerant genotypes under one hour low light treatment. However, no significant differences in gene expression levels for the five genes were observed after two days of stress treatment for tolerant and susceptible genotypes. The genotypes and markers associated with traits identified in this study, after further evaluation, can be used to develop more productive rice varieties for low light affected regions.en_US
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810192807
dc.keywordsLow light tolerance, mapping, marker-trait association, gene expression, riceen_US
dc.language.isoEnglishen_US
dc.pages[18], 118p.en_US
dc.publisherCollege of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiamen_US
dc.subBiotechnology and molecular Biologyen_US
dc.subjectRiceen_US
dc.subjectGenetic mapsen_US
dc.themeAcademic Researchen_US
dc.these.typePh.Den_US
dc.titleMolecular mapping for low light intensity tolerance using the contrasting rice genotypes of Eastern Indiaen_US
dc.typeThesisen_US
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