ARS | Publication request: MAPPING SHEATH BLIGHT RESISTANCE QTLS IN RICE

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 1, 2005
Publication Date: January 1, 2006
Citation: Sharma, Arun, Kepiro, J.L., Fjellstrom, R.G., Pinson, S.R., Shank, A.R., McClung, A.M., Tabien, R. 2006. Mapping sheath blight resistance QTLs in rice [abstract]. Plant and Animal Genome Conference Proceedings. p. 162.

Technical Abstract: Sheath blight (SB), caused by fungus Rhizoctonia solani, is a destructive disease of rice (Oryza sativa) causing severe loss in grain yield and quality each year throughout the world. Resistance has been reported to be horizontal and quantitative, and does not follow the gene-for-gene model. To facilitate the identification of QTLs for SB resistance, a mapping population was developed by crossing two japonica rice cultivars, Rosemont (semi-dwarf and susceptible to SB) and Pecos (tall and tolerant to SB). F2-derived F3 families were screened for susceptibility to SB disease in inoculated field plots during 2002 and 2003 in Texas. Genetic analysis of 279 lines in the mapping population was initiated in May 2005 using leaf tissue from the F3 progeny rows. For high throughput SSR markers genotyping, ABI 3100 Genetic Analyzer and Li-Cor 4200 genetic analysis systems are being used which allow multiplexing of differently labeled primer pairs and generation of ~400 data points per day. Preliminary mapping analysis of 108 polymorphic markers with JoinMap 3.0 revealed that the linear order of the markers is in good agreement with the IRMI-2003 map available at http://www.gramene.org. The average inter-marker distance is less than 20 cM with a few exceptions. Some thirty additional SSR markers are being screened to fill in these gaps for a total of 140 SSR markers. The final genetic linkage map construction and QTL analysis will be presented and results of these findings will be discussed.