Quantitative Trait Loci for Vegetative Stage Heat Stress Tolerance in Rice Using Differential Leaf Damage Assessed By Ion Leakage.

Heat stress affects all stages of rice crop development. Previous research has focused on identifying heat stress tolerance during flowering and grain development but little is known about genetic mechanisms related to vegetative stage tolerance. We used a previously well characterized heat tolerant variety N22, a sensitive variety IR64 and a biparental mapping population of 182 recombinant inbred lines to identify quantitative trait loci (QTL) for various components of heat stress tolerance. Our experiments showed that leaf tissue from heat stress-exposed plants exhibited significantly (P=0.05) more ion leakage than control plants and ‘N22’ was significantly more tolerant than ‘IR64’. Using a linkage map developed from 689 single nucleotide polymorphism markers, we identified xyz QTL contributing xyz to xyz% phenotypic effect. Future research is focused on finding the candidate genes for this component of heat stress tolerance using RNA sequencing.