Identification and Mapping of Adult Plant Stripe Rust Resistance in Soft Red Winter Wheat
Christopher, Mark David
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Since 2000, stripe rust, caused by the fungal pathogen (Puccinia striiformis Westend. f.sp. tritici Eriks.) has resulted in yield losses of wheat (Triticum aestivium L.) in the United States, that exceeded the combined losses of leaf rust (Puccinia triticina Eriks.) and stem rust (Puccinia gramins Pers.:Pers f. sp. Tritici Eriks. E. Henn.). The objectives of this study are to identify and map adult plant stripe rust resistance quantitative trait loci (QTL) in soft red winter (SRW) wheat that are effective against race PST-100, which is the predominant race of the pathogen in the eastern U.S. Adult plant resistance (APR) was characterized in the resistant wheat lines â USG 3555â , VA00W-38, and â Coker 9553â . Resistance in each of the lines was evaluated in populations derived from crosses with susceptible lines â Neuseâ , Pioneer Brand â 26R46â , and VA01W-21, respectively. On chromosomes 1AS, 4BL, and 7D of USG 3555, QTL were identified that explain on average 12.8, 73.0, and 13.6 percent of the variation for stripe rust infection type (IT), and 13.5, 72.3, and 10.5 percent of the variation for stripe rust severity. A QTL from Neuse was identified on 3A that on average explains 10.9 percent of the variation for IT and 13.0 percent of the variation for severity. On chromosomes 2AS and 4BL of VA00W-38, QTL were identified that on average explain 58.9 and 19.3 percent of the variation for stripe rust IT, and 51.9 and 12.1 percent of the variation for severity. On chromosomes 6BL and 3BL of Pioneer 26R46, QTL were identified that on average explain 8.9 and 2.1 percent of the variation for IT and 11.7 and 3.9 percent of the variation for severity. Coker 9553 possesses the QTL on 4BL that is also present in USG 3555 and VA00W-38. The SSR markers, Xgwm296, Xbarc163, and Xwmc756 were tightly linked to QTL on chromosomes 2AS, 4BL, and 6BL, respectively, and their use and development of additional diagnostic markers will facilitate the incorporation and pyramiding of stripe rust resistance QTL into SRW wheat lines via marker-assisted selection.
- Doctoral Dissertations