Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/15/2004
Publication Date: 12/1/2004
Citation: McClung, A.M., Shank, A.R., Marchetti, M.A., Bormans, C., Jodari, F., Johnson, C.W., Park, W.D., Fjellstrom, R.G. 2004. Marker assisted breeding for improving disease resistance in U.S. rice cultivars. Texas Plant Protection Conference. p. 27.
Technical Abstract: Two important diseases of rice worldwide are rice blast (Pyricularia grisea) and sheath blight (Rhizoctonia solani) disease. These fungal diseases decrease yield and rice milling quality. U.S. breeders have been successful in developing cultivars with stable resistance to blast disease primarily because the environment is not as conducive to disease development as in other countries. This has involved screening hundreds of breeding lines each year in inoculated greenhouse and field tests. After some three decades of this work, relatively accurate screening techniques have been developed and the major genes for blast resistance in U.S. rice germplasm are quite well understood. Less is understood about sheath blight disease and limited progress has been made in developing tolerant cultivars. Molecular marker technology provides the opportunity to develop DNA markers that are associated with major blast resistance genes in U.S. germplasm. Having markers will facilitate the development of improved cultivars with less laborious field testing, will allow genes to be pyramided in unique combinations for broad spectrum resistance, and will facilitate the identification and introgression of novel resistance genes from unadapted germplasm. We have been successful in developing markers that are closely linked with five major blast resistance genes known to occur in U.S. germplasm. This technology has been transferred to U.S. rice breeding programs and is being used to enhance conventional breeding methods. Our next step will be to apply this expertise to the development of DNA markers associated with sheath blight disease which is more complexly inherited and difficult to evaluate.