Genomic regions associated with grain yield under drought stress in wheat (Triticum aestivum L.)

Water deficit stress (WDS) is a serious constraint to wheat productivity in rain-fed and limited irrigation environments. Identifying genomic regions responsible for grain yield (GY) under WDS will aid in understanding the genetics of drought tolerance (DT) and development of DT cultivars. A population of 206 recombinant inbred lines derived from WL711/C306 was phenotyped for GY and related traits under water deficit and irrigated conditions in seven different environments to identify genomic regions associated with eleven yield related traits. Both the parents contributed positive alleles for the traits studied. A novel genomic region for GY under WDS, qGYWD.3B.1 was detected on chromosome 3BS of wheat. The yield enhancing allele under drought stress at this locus was contributed by DT parent C306. This genomic region explained 18.7 % of phenotypic variation for GY under WDS and co-located with genomic regions for GY components. Another novel, consistent genomic region for GY under WDS, qGYWD.3B.2 explained 19.6 % of phenotypic variation with positive allele coming from drought susceptible parent WL711. A novel genomic region for drought susceptibility index for GY, qDSIGY.4A.1 was consistently detected in six of seven environments explaining 15.6 % of phenotypic variation. Other important genomic regions for GY and biomass under WDS were mapped on chromosomes 7BL and 6AS, respectively. Fine mapping of the major QTLs on chromosome 3BS will enable identification of robust markers and candidate genes for marker-assisted breeding for DT in wheat.