Leaf rust resistance on chromosome 7B of common wheat

Puccinia triticina, which causes leaf rust of wheat, is a variable pathogen that regularly overcomes monogenic major-gene resistance resulting in significant yield losses. Stacking minor resistance genes to supplement major gene resistance may offer a more sustainable solution to controlling this disease. The objective of this study was to evaluate multiple biparental populations for quantitative forms of resistance. Doubled haploid populations Carberry/AC Cadillac, Stettler/Red Fife and Vesper/Lillian were grown and assessed for adult plant leaf rust resistance in nurseries near Swift Current, Saskatchewan, in 2011 to 2015, Morden, Manitoba, in 2015, and Lincoln, New Zealand, in 2014. The lines of the populations were genotyped using the 90K Infinium iSelect assay and quantitative trait locus (QTL) analysis was performed. Two QTL contributing to resistance were identified near the telomeric regions of the long and short arms of chromosome 7B with resistance derived from Vesper, AC Cadillac and Red Fife. The QTL, which expressed in multiple environments, should contribute to resistance when stacked with other leaf rust resistance genes during the
breeding of commercial cultivars.