Yellow rust (YR), caused by Puccinia striiformis f. sp. tritici, reemerged as an important wheat disease in Norway with the recent incursion of the new race groups in 2014. Thus, little is known about the YR resistance of the current Norwegian wheat materials. In addition, since the race-specific resistance is easy to break by the rapid pathogen evolution, race non-specific resistance is needed to obtain more sustainable cultivar resistance. In order to assess the field resistance of Norwegian wheat materials, thirteen trials were conducted in seven locations across three European countries and China using a Nordic spring wheat association panel consisting of 300 lines. The panel, genotyped with the 25K SNP chip, includes current and historically important cultivars and breeding lines grown in Norway. Genome wide association studies (GWAS) identified ten consistent QTL across environments on chromosomes 1B, 2A, 3B, 5A, 5B ,6A, 6B and 7A, respectively. One robust QTL on the long arm of chromosome 6A was detected in 11 out of the 13 tested environments. As YR races are likely different in Europe and China, we hypothesize that the 6A QTL might be driven by a race non-specific gene, because of the consistent detection in all four tested countries. In addition, an independent Norwegian wheat breeding panel was used for validating the haplotype effect caused by the 6A QTL. Significant differences were detected between resistant and susceptible haplotypes in all four tested trials in Norway. The robustness and consistency of the 6A QTL suggest that it can be broadly exploited in marker assisted selection to improve YR resistance.
