A durum wheat adult plant stripe rust resistance QTL and its relationship with the bread wheat Yr80 locus.

Key Message: A stripe rust resistance QTL in durum wheat maps near the bread wheat Yr80 locus with the latter reduced to 15 candidate genes. Some wheat adult plant resistance (APR) genes provide partial resistance in the later stages of plant development to rust diseases and are an important component in protecting wheat crops from these fungal pathogens. These genes provide protection in both bread wheat and durum wheat. Here, we have mapped APR to wheat stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici, in a cross between durum cultivars Stewart and Bansi. Two resistance QTLs derived from the Stewart parent were identified in multi-generational field trials. One QTL is located on chromosome 1BL and maps to the previously identified Yr29/Lr46/Sr58/Pm39 multi-pathogen APR locus. The second locus, located on chromosome 3BL, maps near the recently described bread wheat APR gene, Yr80. Fine mapping in durum and bread wheat families shows that the durum 3BL locus and Yr80 are closely located, with the later APR gene reduced to 15 candidate genes present in the Chinese Spring genome sequence. Distorted segregation of the durum 3BL region was observed with the Stewart locus preferentially transmitted through pollen when compared with the equivalent Bansi region.