Identification and genetic analysis of rust resistance genes in wheat for marker-assisted selection

Wheat rusts cause severe reductions in wheat yield around the globe. Due to economic losses caused by rust pathogens, they are priority-one diseases for breeding in Canada and other countries. Given the importance of breeding for rust resistance in wheat, various wheat variety registration processes around the world require a minimum resistance threshold to rust pathogens. Considering the coevolution of rust pathogens and their host, these fungi can evolve quickly and overcome resistance in cultivated wheat varieties. Thus, identification, characterization, and breeding using novel resistance sources can result in optimal yields to ensure food security. Various sources of rust resistance actively used in wheat breeding include landraces and wild accessions in addition to international modern wheats. A typical rust resistance evaluation process involves the identification of resistant germplasm through phenotypic analysis, followed by the development of mapping populations, and finally, introgression into breeding material using phenotypic and marker-assisted selection. In this chapter, we outline greenhouse phenotyping and linkage analysis methodologies to identify loci underlying rust resistance and use of linked molecular markers for wheat breeding.