Tan spot, caused by Pyrenophora tritici-repentis (Ptr), is one of the major foliar diseases in both durum and common wheat. To understand the genetic architecture of tan spot resistance and facilitate marker-assisted selection in wheat breeding, numerous bi-parental QTL mapping and genome-wide association (GWA) studies had been conducted, from which over 100 QTL were identified. The previous mapping studies proved that tan spot resistance is a quantitative trait controlled by genes either conferring resistance to a specific race/host-selective toxin (HST) or providing race-nonspecific resistance. In this work, we constructed a consensus linkage map by integrating 18 individual durum and common wheat linkage maps. The previously identified QTL from 15 bi-parental mapping populations and three GWA populations were projected to the consensus map. In total, 17 metaQTL were detected including the genes known to confer sensitivity to HSTs, five of which were likely race-nonspecific. Ptr race 1 (producing HSTs ToxA and ToxC) is the most prevalent race in the Northern Great Plains, a major durum and hard red spring wheat growing region in North America. Our candidate gene mapping indicated that the allele conferring insensitivity to Ptr ToxC was almost fixed in the North Dakota State University (NDSU) durum wheat breeding population. On the contrary, alleles for race-nonspecific resistance QTL were rare among NDSU durum wheat breeding material. These results suggest that integrating the race-nonspecific QTL will provide more stable resistance to tan spot in the NDSU durum wheat breeding program.

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