Identification of genomic regions controlling physiological and morphological traits of bread wheat under terminal heat stress

In order to identify genomic regions with main, epistatic, and QTL×environment interaction effects for some of the phenological and morphological traits in bread wheat, an experiment with 167 recombinant inbred lines and their parents (‘SeriM82’ and ‘Babax’) was conducted at Research Farm of the Agricultural Research Station of Sistan in 2015-16 cropping season. The experiment was carried out using two alpha lattice designs with two replications under non-stress and terminal heat stress conditions. Seven traits including days to maturity (DM), grain filling duration (GFD), maximum quantum efficiency of photosystemII (Fv/Fm), cytoplasmic membrane stability (CMS), grains per spike (GPS), grain yield (GY) and thousand grain weight (TGW) were measured. There were significant differences among the genotypes for all studied traits and maximum correlation was observed between GY and Fm/Fv (r = 0.86**). QTL analysis was conducted by Mixed-Model based composite interval mapping (MCIM) method. A total of 33 main-effect QTLs for studied traits were detected. Phenotypic variances explained by these QTLs varied from 7.04% for GFD to 19.41% for TGW. The major Qtgw7D (R2 = 19/41) was identified near the marker of acc/cat-10 and after validation can be used in marker-assisted selection (MAS) in order to produce heat tolerant wheat varieties.