Stripe rust, a significant wheat disease caused by the fungus Puccinia striiformis f.sp. tritici, has become
more aggressive in recent years, affecting previously resistant wheat cultivars and causing severe yield
losses. To combat this, our project focused on identifying genetic resistance to stripe rust using
advanced breeding techniques.

We studied three large wheat populations, known as nested association mapping (NAM) populations,
which included 16 recombinant inbred line (RIL) families. These populations were developed by crossing
susceptible spring wheat cultivars with highly resistant donor lines. Field experiments were conducted in
multiple locations in Canada to assess stripe rust severity in disease nurseries. Additionally, the
populations were genotyped using a high-density SNP marker assay, which allowed us to construct
detailed genetic maps.

Our genetic analyses identified 226 QTL regions using the three NAM populations and 76 using
individual RIL families that contribute to stripe rust resistance. Some of these regions were consistently
detected across different environments, indicating their stability and potential for breeding applications.
A subset of these QTLs, particularly those with major effects, were used to develop breeder-friendly
molecular markers (KASP markers) to facilitate marker-assisted selection (MAS) in wheat breeding
programs.

Furthermore, resistant donor lines identified in this study have been incorporated into wheat breeding
programs to develop new, resistant wheat cultivars. These advanced breeding lines are currently being
evaluated for their potential release as commercial cultivars. The high-density genetic maps generated in
this project also provide a valuable resource for future research, including fine mapping and gene cloning
efforts, to further enhance stripe rust resistance in wheat.