Selection of Hard Red Winter Wheat Lines with Diverse Resistance to Leaf Spot Diseases

Tan spot and Septoria nodorum blotch cause serious yield losses in winter wheat in North Dakota as the majority of commercially grown cultivars are susceptible. This study aimed to identify lines with improved resistance for use as breeding parents. First, advanced NDSU breeding lines and alternative sources of resistance were inoculated with fungal isolates and tested for necrotrophic effector sensitivity. Second, resistant lines were derived from a highly heterogeneous recurrent mass selection F2 population using single seed descent inbreeding coupled with selection for resistance. Finally, the best performers from both experiments (total of 52 lines) were evaluated to confirm resistance. In addition the 52 lines were analyzed with markers that detect Tsn1 and the 1RS rye translocation. Twenty lines were identified with simultaneous resistance to four or three fungal isolates and insensitivity to three, two, or one necrotrophic effectors (of which 11 can be used directly as new parents).North Dakota Wheat CommissionMinnesota Wheat Research Promotion Counci