|Christopher, Mark -|
|Liu, Shuyu -|
|Hall, Marla -|
|Johnson, Jerry -|
|Milus, Gene -|
|Griffey, Carl -|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2011
Publication Date: January 11, 2012
Citation: Christopher, M.D., Liu, S., Hall, M.D., Marshall, D.S., Fountain, M.O., Johnson, J., Milus, G., Campbell, K., Chen, X., Griffey, C.A. 2012. Identification and mapping of adult plant stripe rust resistance in soft red winter wheat VA00W-38, Pioneer brand 26R46, and Coker 9553. Crop Science. 53:871-879. Interpretive Summary: In order to develop new wheat varieties with durable resistance to wheat rust diseases, numerous minor genes must be accumulated in desirable genetic backgrounds. This accumulation through breeding must use DNA-based molecular markers to tag and follow the minor genes in segregating populations. This research identifies three such molecular markers found individually in the wheat varieties VA00W-38, Pioneer 26R46, and Coker 9553.
Technical Abstract: Since 2000, many of the previously effective wheat (Triticum aestivum L.) seedling stripe rust (pathogen Puccinia striiformis Westend. f.sp. tritici Eriks) resistance genes have become ineffective to the new more aggressive races of the pathogen. Because seedling resistance genes work on a gene for gene basis, seedling resistance to stripe rust is generally short-lived due to the ease with which the pathogen evolves virulence to a single resistance gene. On the other hand, adult plant resistance (APR) and high temperature adult plant (HTAP) resistance tends to be much more durable and effective against multiple races of a pathogen. The Virginia Tech experimental line VA00W-38 has been identified as having very good adult plant resistance (APR) to stripe rust. This resistance was characterized in a population derived from a cross between VA00W-38 and Pioneer Brand ‘26R46’, which is moderately susceptible to stripe rust. The mapping population consists of 182 recombinant inbred lines (RILs), which were evaluated in field tests for stripe rust infection type in Georgia in 2008 and 2009, and for infection type and severity in North Carolina in 2009 and 2010. Field tests were inoculated with race PST-100, which is the predominant race in the southeast. Genome wide molecular screens using 143 simple sequence repeats (SSR) and 405 Diversity Array Technology (DArT) markers were employed to identify quantitative trait loci (QTL) for stripe rust resistance. QTL were identified on chromosomes 2AS and 4BL of VA00W-38, explaining on average 56.6%, and 16.9% of the variation for stripe rust resistance respectively, and on 6BL and 3BL (9.9% and 2.7%) of Pioneer 26R46. Markers Xgwm296, Xbarc163, and Xwmc756, were most tightly linked to QTL on chromosomes 2AS, 4BL, and 6BL respectively. Use of these markers and development of additional diagnostic markers will facilitate the incorporation and pyramiding of stripe rust resistance into soft red winter (SRW) wheat lines via marker-assisted selection (MAS).