MAPPING WHEAT QTLS FOR GRAIN YIELD RELATED TRAITS UNDER HIGH TEMPERATURE STRESS

Stress induced by high temperature represents a major constraint over wheat production in many production areas. Here, the comprehensive coverage of the wheat genome achievable using single nucleotide polymorphism markers was exploited to carry out a genetic analysis targeting yield components in plants exposed to high temperature stress. The mapping population was a set of doubled haploid lines derived from a cross between the cultivars Yecora Rojo and Ksu106. Both of the parental cultivars and their derived population were tested in the field in two locations over two consecutive seasons; at each site, two sowing dates were included, with the later sowing intended to ensure that the plants were exposed to high temperature stress during the grain filling period. Composite interval mapping detected 93 quantitative trait loci influencing grain yield and some related traits, along with 20 loci associated with a "heat susceptibility index" (HSI). The loci were distributed over all 21 of the wheat chromosomes. Some of these loci were of large enough effect to be considered as candidates for the marker-assisted breeding of high temperature tolerance in wheat.