Mapping of QTLs for seed longevity under simulated climate change conditions in rice

Abstract

An experiment was carried out at ICAR-NRRI, Cuttack by taking 300 rice germplasm newlinelines from different rice ecologies collected from Gene Bank, ICAR-NRRI, Cuttack during 2020- newline21 for the study of seed longevity. A representative panel population comprising 150 rice newlinegermplasm lines was developed from the diverse population of 300 rice genotypes based on their newlinemean Germination Percentage (GP) under accelerated ageing condition. The panel population was newlinesubjected to different treatments of atmospheric temperature and RH simulated for the study of newlinevariability in seed longevity parameters. The panel was also genotyped by using 145 polymorphic newlineSSR markers. Six treatments were framed including the control (T1-freshly harvested seeds), newlinewhich were analyzed for eight germination and related parameters. The germplasm lines, namely newlineAdira-1and Koompallai were found with high mean values for different seed quality traits under newlinevariable temperature and moisture conditions that are effective for selection in further breeding. newlineThe results revealed, deterioration was maximum under combination of high temperature and newlinehigh relative humidity than their individual effects. A strong positive correlation of germination newlinepercentage (GP) with Seed Vigor Index-I (SVI), Seed Vigor Index-II (SVII) and speed of newlinegermination (SOG) was found under variable temperature and moisture conditions. The diversity newlineestimation revealed a mean gene diversity value of 0.5824and the mean polymorphic information newlinecontent (PIC) value of 0.5224 in the population which means the population was diverse and newlinemakers were informative. The 150 panel population was broadly classified into five clusters as newlinerevealed in the cluster analysis based on phenotypic mean values under accelerated ageing and newline3months of storage at room temperature (300C ± 2, 60-70% RH) followed by 500C for 2 days. newlineThe structure analysis classified the panel population into six genetic structural groups at k=6 newlineunder both accelerated ageing and 3 months of storage at room temperature (300C ± 2, 60-70% newline