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Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Dist. - Nadia, West Bengal PIN - 741 252

The university established in 1974, has completed five decades of its existence as the pioneer institute of Agricultural Education, Research and Extension. The main objective of this Viswavidyalaya is to provide facilities for the study of Agriculture, Horticulture and Agricultural Engineering. It is also to conduct researches in these sciences and undertake the educational and extension programmes in agriculture among the rural clientele base, keeping in view the requirements of the state.

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Subject: Genetics and Plant Breeding × Author: Saha Shoumik × Start date: 2005 ×
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    ThesisItemOpen Access
    IDENTIFICATION OF RICE GENOTYPES WITH ACCELERATING RECOVERY FROM PHOTOPROTECTION AND THEIR GENETIC ANALYSIS
    (GENETICS AND PLANT BREEDING, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia – 741252, 2023-12-20) Saha Shoumik; Dr. Somnath Bhattacharyya
    Rice cultivation in the eastern and north-eastern parts of India faces biotic and environmental challenges, including changing climatic conditions and extreme light fluctuations, which reduce crop yield potential by up to 35-40% in Kharif. The plant undergoes photoprotection mode by increasing nonphotochemical quenching (NPQ) in high light intensity (>1200 μmole m-2s-1 PPFD ), which attenuates photosystem II yield (ɸPSII) drastically. The plant remains in photoprotection mode (reduced ɸPSII and high NPQ) even after light intensity becomes normal (<1000 PPFD) for a more extended period (usually > half an hour). The study aims to identify rice genotypes with quick photoprotection recovery (QPR) ability and allelic variations of the genes controlling the traits. However, phenotyping QPR requires more than forty-five minutes/genotype to measure the chlorophyll fluorescence parameters in progressive actinic light (200-1800 μmole m-2s-1 PPFD) after dark adaptation. Swarnaprabha, Shatabdi, GB1, and Bidhan Suruchi showed QPR ability as observed from the less gap between theoretical and observed ɸPSII yield at 400 PPFD as well as a larger difference between NPQ1800 -NPQ400 after twenty minutes of exposure at six different increasing PPFD, whereas Swarna, Chotogora, and Srabani behave contrarily. The study finds that instantly (2 minutes) measured A400/A1800 ratio in 8-10 days old flag leaves strongly associated with NPQ1800 -NPQ400 and ɸPSII400- ɸPSII1800 with R2 value 0.81 and 0.77 respectively. In a panel of ninety-six genotypes using the QPR data by the newly proposed methodology and 7K SNP genotyping data, GWAS identified that the region (LOD>3) possesses the genes reported earlier for photoprotection recovery in rice and other plants. QTL analysis further validated new methodology in a RIL population developed from a contrasting parental pair Swarnaprabha x IR64. The GWAS and QTL analyze the regions carrying known photoprotection-related genes like OsPsbS1, OsLUT2, OsVDE, OsZEP, OsPGPL2, OsbZIP72 located on chromosomes 1, 4, 8, 9. Genotypes with quick photoprotection recovery identified and further analyzed with existing methodology confirmed their QPR ability. A positive association between A400/A1800 ratio and yield and biomass was observed in RIL with R2 values of 0.11 and 0.17, respectively. The newly identified methodology for the QPR will be used for easier introgression of the traits in popular cultivars of the zone. The identified genotypes, genes, and QTLs can be used to improve yield potential and allele mining.