Introgression of a drought insensitive grain yield QTL for improvement of four Indian bread wheat cultivars using marker assisted breeding without background selection

In wheat, a major yield QTL (Qyld.csdh.7AL) contributing ~ 20% to the variation for grain yield under drought was introgressed into each of the four Indian wheat cultivars (HUW234, HUW468, K307 and DBW17) with an objective to develop high yielding drought tolerant genotypes. The marker Xwmc273.3 linked to the yield QTL was used for marker assisted foreground selection, which was followed by phenotypic selection leading to the development of 55 advanced lines. These lines were evaluated during the crop seasons 2015–2016 and 2016–2017 under irrigated and rainfed conditions at two locations (Meerut and Niphad), which differed for agro-climatic conditions. Under irrigated condition at Niphad, three lines gave 14.9–25.7% higher yield relative to the corresponding genotypes HUW234 and DWB17 that were used for introgression. Similarly, under rainfed condition at Meerut, one line gave 25.5% higher yield relative to the corresponding genotype HUW234. The high yield in the selected lines was attributed to number of grains per ear, grain weight, tiller number, biomass and lower canopy temperature. The line giving higher yield under rainfed condition also had low stress sensitivity index suggesting its ability to tolerate water-stress. The high yielding lines may be used for testing in a variety development programme. The study is yet another example of the successful use of MAS in combination with phenotypic selection for development of high yielding wheat genotypes for rainfed and irrigated conditions.