Resistance to Tan Spot and Stagonospora nodorum Blotch in Wheat-Alien Species Derivatives.

Tan spot (caused by Pyrenophora tritici-repentis) and Stagonospora nodorum blotch (SNB) (caused by Stagonospora nodorum) are destructive fungal diseases of wheat (Triticum aestivum) throughout the world. Host plant resistance is thought to be an efficient and economical method of control. The objective of the present study was to identify novel sources of tan spot and SNB resistance in wheat genotypes derived from the crosses between wheat and alien species. Evaluations were conducted at the seedling stage in a growth chamber with 100% relative humidity. For each genotype, three replications were used for each disease. Among the 199 wheat-alien species derivatives evaluated, 65 exhibited resistance to tan spot and 30 showed resistance to SNB similar to BR34, a Brazilian wheat line used as the resistant control. Eleven derivatives were resistant to both diseases. Reactions of the derivatives and their respective wheat parents to tan spot and SNB suggest that resistance genes in the derivatives are derived from alien species. These derivatives can serve as desirable bridges for introgression of resistance genes from alien species to cultivated wheat, and could contribute novel and effective tan spot and SNB resistance to wheat breeding.