Wednesday, November 7, 2007
274-6
Identification and Mapping QTL for High Temperature Adult Plant Resistance to Stripe Rust in Wheat (Triticum aestivum L.).
Dipak K. Santra1, Meenakshi Santra1, Xianming Chen2, Kimberly G. Campbell2, and Kimberlee Kidwell3. (1) Washington State University, Crop & Soil Sci. 201 Johnson, PO Box 646420 WA St. Univ., Pullman, WA 99164-6420, (2) USDA-ARS Wheat Genetics, Quality, Physiology and Disease Research Unit, 209 Johnson Hall, Washington State University, Pullman, WA 99164-6420, (3) College of Agricultural, Human, and Natural Resource Sciences, Washington State University, 423 Hulbert Hall, PO Box 646243, Pullman, WA 99164-6243
High-temperature, adult-plant (HTAP) resistance to stripe rust from the winter wheat cultivars ‘Stephens' and ‘Druchamp' have protected wheat crops from this disease for nearly 30 years. The objectives of this study were to: (1) identify major QTL for HTAP resistance in Stephens and Druchamp through genetic linkage analysis; and (2) develop DNA markers for HTAP resistance genes for use in marker-assisted breeding. Mapping populations consisted of 101 recombinant inbred lines (RILs) from Stephens (resistant) x Michigan Amber (susceptible), named SMRILs and 100 RILs developed from Druchamp (resistant) x Michigan Amber (susceptible), named DMRILs. F5 F6 and F7 RIL derivatives were evaluated at one location in 1996, 1997 and 1998, respectively, whereas F8 and F9 derivatives were evaluated at four locations in 2006 and 2007, respectively. Mean values for infection type (IT), as well as area under disease progression curve (AUDPC) values for each RIL were calculated from disease data recorded on three different dates for each site year. The 101 SMRILs were evaluated with 258 SSR and 1 STS markers for genetic linkage map construction. Two QTL associated with HTAP resistance in Stephens were identified; however, variation in the level of significance of associations was detected among locations and across years. Q.htap-1 (LOD=6.45-13.66, R2 =0.23-0.44, P<0.0001) and Q.htap-2 (LOD=5.54-7.74, R2 =0.20-0.26, P<0.0001) were detected on chromosome 6B within a 9.4 cM region flanked by Xbarc101 and Xbarc211 and a 17.6 cM region flanked by Xgwm508.2 and Xgwm132, respectively. The 100 DMRILs were genotyped with 125 of 264 polymorphic SSR markers. The population is currently being genotyped with the additional polymorphic markers, and combined marker data will be used for linkage and QTL mapping. We intend to develop breeder friendly molecular markers for use in marker-assisted breeding strategies to efficiently incorporate HTAP resistance into regionally adapted cultivars.