Identifying and Utilizing High-Temperature Adult-Plant Resistance to Combat Stripe Rust in Wheat.
Kimberlee K. Kidwell1, Dipak K. Santra1, Cristobal Uauy2, Xiaming Chen3, Kimberly G. Campbell3, and Jorge Dubcovsky2. (1) Washington State University, 201 Johnson Hall, Pullman, WA 99164-6420, (2) University of California Davis, Dept of Agronomy & Range Science, Davis, CA 95616-8515, (3) USDA-ARS Wheat Genetics, Quality, Physiology and Disease Research Unit, 209 Johnson Hall, Washington State University, Pullman, WA 99164-6420
Stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici) is one of the most destructive diseases of wheat (Triticum aestivum L.) grown worldwide. Two major types of genetic resistance have been identified; seedling resistance that is race-specific and is not durable, and high-temperature adult-plant (HTAP) resistance that is race nonspecific and durable. High levels of HTAP resistance have been identified in T. dicoccoides, which is a tetraploid, as well as in several hexaploid wheat cultivars. HTAP resistance from the winter wheat cultivars ‘Stephens' and ‘Druchamp' have provided significant levels of protection from stripe rust in winter wheat for over 25 years. Full utilization of these sources requires efficient strategies for incorporating HTAP resistance into susceptible germplasm, as well as an enhanced understanding of the underlying mechanisms governing this type of resistance. The objectives of this research are to: 1) clone the HTAP resistance gene Yr36 on chromosome 6BS from T. dicoccoides using a map-based cloning approach; and 2) identify major QTL for HTAP resistance in Stephens and Druchamp through genetic linkage analysis. We recently identified a major QTL associated with HTAP resistance on chromosome 6BS in Stephens, and flanking markers associated with this region have been identified. Comparative mapping results indicate that this QTL region from Stephens partially overlaps with the chromosomal location of Yr36 in T. dicoccoides. We intend to develop breeder friendly molecular markers for use in marker-assisted selection strategies to efficiently incorporate HTAP resistance into regionally adapted cultivars.