G. Liu, Rice Research and Extension Center, University of Arkansas, Stuttgart 72160;
Y. Jia and
A. McClung, United States Department of Agriculture–Agricultural Research Service, Dale Bumpers National Rice Research Center, Stuttgart, AR 72160;
J. H. Oard, School of Plant, Environmental and Soil Sciences, LSU AgCenter, Louisiana State University, Baton Rouge 70803;
F. N. Lee, Rice Research and Extension Center, University of Arkansas, Stuttgart; and
J. C. Correll, Department of Plant Pathology, University of Arkansas, Fayetteville 72701
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Accepted for publication 30 July 2012.
Rice sheath blight disease, caused by Rhizoctonia solani AG1-1A, is one of the most destructive rice diseases worldwide. Utilization of host resistance is the most economical and environmentally sound strategy in managing sheath blight (ShB). Ten ShB quantitative trait loci (QTLs) were previously mapped in a Lemont × Jasmine 85 recombinant inbred line (LJRIL) population using greenhouse inoculation methods at an early vegetative stage. However, confirmation of ShB-resistant QTLs under field conditions is critical for their utilization in marker-assisted selection (MAS) for improving ShB resistance in new cultivars. In the present study, we evaluated ShB resistance using 216 LJRILs under field conditions in Arkansas, Texas, and Louisiana during 2008 and 2009. We confirmed the presence of the major ShB-QTL qShB9-2 based on the field data and also identified one new ShB-QTL between markers RM221 and RM112 on chromosome 2 across all three locations. Based on the field verification of ShB evaluations, the microchamber and mist-chamber assays were simple, effective, and reliable methods to identify major ShB-QTLs like qShB9-2 in the greenhouse at early vegetative stages. The markers RM215 and RM245 were found to be closely linked to qShB9-2 in greenhouse and field assays, indicating that they will be useful for improving ShB resistance in rice breeding programs using MAS.
This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2013.