Abstract
One of the most important tools to identify and validate rust resistance gene function is by producing loss-of-function mutants. Mutants can be produced using irradiation, chemicals, and insertions. Among all the mutagens, ethyl methanesulfonate (EMS) and sodium azide are most favored because of the ease of use and generation of random point mutations in the genome. The mutants so produced facilitate the isolation, identification and cloning of rust resistance genes. In this chapter we describe a protocol for seed mutagenesis of wheat with EMS and sodium azide.