Location: Plant Science ResearchTitle: Identification and mapping of adult plant stripe rust resistance in soft red winter wheat cultivar USG 3555) Author
Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/11/2012
Publication Date: 12/11/2012
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 cultivar USG 3555. Crop Science. 132:53-60. 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 two such molecular markers found in the wheat variety USG3555.
Technical Abstract: Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis Westend. f.sp. tritici Eriks., as until recently, breeding programs in the eastern U.S. have not focused on this disease. Prior to the spring of 2000, stripe rust had not been identified in Virginia, yet it has been found in each of the subsequent years and was widespread and severe in the Commonwealth in 2005 and 2010. The 2010 growing season brought evidence that new races with virulence to the previously effective and frequently deployed gene Yr17 are present in the United States. The breakdown of Yr17 highlights the need to identify and characterize novel sources of durable resistance to employ in breeding programs. The recently released soft red winter (SRW) wheat cultivar USG 3555 has very effective adult plant resistance (APR) to stripe rust. This resistance was characterized in a population derived from a cross between USG 3555 and ‘Neuse’, which is susceptible to stripe rust. The mapping population consists of 99 recombinant inbred lines (RILs), which were evaluated for reaction to stripe rust in field trials in North Carolina in 2010 and 2011 for infection type and severity. Fields were inoculated with race PST-100, which is the predominant race in the southeast. Genome wide molecular screens using 119 simple sequence repeats (SSR) and 560 Diversity Array Technology (DArT) markers were employed to identify quantitative trait loci (QTL) for stripe rust resistance. QTL were identified on chromosomes 1AS, 4BL, and 7D of USG 3555, explaining on average 13.1%, 72.7%, and 12.0% of the variation for stripe rust resistance respectively, and on 3A (11.9%) of Neuse. Flanking markers Xbarc163 and Xwmc692 linked to the QTL on chromosome 4BL and development of additional tightly linked markers will facilitate the incorporation and pyramiding of stripe rust resistance into soft red winter (SRW) wheat lines via marker-assisted selection (MAS).