Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: June 1, 2011
Citation: Poole, G., Smiley, R., Paulitz, T.C., Campbell, K. 2011. Identifying quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in two spring wheat populations. Phytopathology. 101: S144. Technical Abstract: Fusarium crown rot (FCR), caused by F. pseudograminearum and F. culmorum, reduces wheat yields in the Pacific Northwest (PNW) of the U.S. by as much as 35%. Currently there is no consistent durable resistance to FCR in PNW wheat cultivars. Significant QTL for crown rot resistance have been documented on chromosomes 1A, 1D, 2B, 3B, and 4B from resistant Australian cultivars. The objective was to identify major QTL for Fusarium crown rot resistance in the Australian spring wheat cultivar ‘Sunco’ to facilitate PNW breeding efforts. Two mapping populations consisting of 151 F5:F6 and 219 F6:F7 recombinant inbred lines (RIL), were derived from crosses between Sunco (partially resistant) by Otis (susceptible) and Sunco by Macon (susceptible), respectively. Plants were inoculated with F. pseudograminearum isolate (006-13) in growth room (seedling), outdoor nursery (adult) and field (adult) assays. Stem base crown tissues of seedling and adult plants were rated for disease severity on 0 to 10 scale during 2008, 2009 and 2010. Five significant QTL were identified on chromosomes 3B, 4B, 4A, and 7A with LOD scores ranging from 3.0 to 23. The most significant QTL was located on chromosome 3BL and inherited from Sunco with maximum LOD scores of 23 and 10 explaining 28% and 23% of the variation, respectively for each population. This is the first report of this unique 3BL QTL for resistance to Fusarium crown rot inherited from Sunco.