Putative Markers associated with Grain weight under Terminal Heat Stress in Bread-Wheat (Triticum aestivum L.)

Terminal heat tolerance is an important breeding target in wheat. Methods of selection for heat tolerance in wheat are limited. The most common approach is the evaluation of yield in nurseries grown under heat stress. The objective of this study was to estimate inheritance of heat tolerance and the grain character in bread wheat by combining molecular marker analysis. The tolerance in bread wheat using a cross between genotypes that were identified previously were utilized to identify SSR markers that are linked to traits associated with terminal heat tolerance. Grain wt. was used as a measure of heat tolerance because this trait was highly correlated with tolerance levels of genotypes. Genotypes WH730 and RAJ4014 were used as tolerant and sensitive parents respectively for generating mapping populations against the study of terminal heat stress respectively. A Recombinant Inbred Line (RIL) mapping population derived from the heat sensitive genotype RAJ4014 and heat tolerant genotype WH730 was evaluated for the heat stress over two years in a replicated trial under timely sown (TS) and late sown (LS) field conditions. The parental lines were screened with approximately 300 SSR (μsatellite) markers out of which about 20% showed polymorphism. Parents and their Recombinant inbred lines (RILs) screened by microsatellite markers for finding allelic variation. Xgwm48, Xgwm55 and Xcfd29 are three markers suggested an application of marker-assisted selection for wheat improvement under terminal heat tolerance.