Identification of QTLs for physiological and productivity traits under drought stress and stability analysis in upland rice oryza sativa l

Abstract

Near Isogenic Introgressed Lines (NIILs) of IR 64 x Binam (IB) and Teqing x Binam newline(TB) were evaluated under non-stress (E1), moisture stress at vegetative stage (E2) and newlinereproductive stage (E3) for identification of QTLs for physiological and productivity traits. High newlineyielding NIILs were superior for productivity traits like, number of panicles per plant, panicle newlineweight, number of grains per panicle, spikelet fertility and also for physiological traits like newlinephotosynthetic rate, relative water content (RWC) and chlorophyll meter (SPAD) reading newlineunder stress indicating their importance for drought tolerance. In all, 61 QTLs in IB NIILs and newline35 QTLs in TB NIILs were detected (Plt0.01) for physiological and productivity traits. newlinePhenotypic variation explained by QTLs ranged from 2.47 to 15.26 per cent in IB NIILs and newline5.54 to 21.12 per cent in TB NIILs. Majority of QTLs detected under drought condition, had newlinefavourable alleles from Binam. The significantly correlated traits were co-located at same newlinemarker locus. Segregation distortion was observed to the extent of 55.38 and 46.48 per cent newlineof the mapped SSR marker loci in IB and TB NIILs, respectively. The SSR markers, RM261, newlineRM21 and RM260 were linked with QTLs for photosynthetic rate, transpiration rate and leaf newlinearea, respectively in both IB and TB NIILs. The SSR markers RM-265, RM-242, RM-197, newlineRM-6 and RM-208 associated with QTLs for plant height at vegetative stage, plant height at newlinematurity, leaf area at maturity, leaf area at vegetative stage and number of tillers per plant, newlinerespectively were common across environments. These consistent and stable QTLs across newlinerecurrent backgrounds or environments are important in MAS for drought tolerance. In G x E newlineanalysis, stability indices like Hernandez desirability index, Lin and Bins superiority index and newlinerelative yield which consider both yield and stability were repeatable with highly significant newlinerank correlations between data sets. Across 14 different approaches, RF-55-254, RF-55-198 newlineand RF-53-253-3-I NIILs were the best for yi