Genomics of Root and Stay-Green Traits to Improve Wheat Adaptation to Late Season Drought

In many wheat cropping regions, water limitation is the primary production constraint. This situation is predicted to be more frequent with future climate change. The stay-green phenotype allows crops to remain green and photosynthesize for longer than standard phenotypes after anthesis which can improve yields under late season drought. Root systems with more roots at depth can contribute by increasing access to deep soil moisture late in the season. To study the genetics of root and stay-green traits in wheat, a multi reference parent nested association mapping (NAM) population was developed. Using the “speed breeding” system of rapid generation advance, over 1500 recombinant inbred lines were generated in approximately 18 months. A novel whole-genome NAM method (WG-NAM) was developed for genome-wide association mapping to identify markers associated with the target traits.