Described herein are methods and materials useful for improving lateral root growth, water uptake, and the yield of grain of cereal grasses grown under drought stress conditions. In particular, the present disclosure provides a quantitative trait locus associated with improved yield under drought stress. The disclosure further provides recombinant DNA for the generation of transgenic plants, transgenic plant cells, and methods of producing the same. The present disclosure further provides methods for generating transgenic seed that can be used to produce a transgenic plant having improved yield under drought stress, and methods for improving yield under drought stress in a cereal grass involving marker assisted selection and backcrossing.