ARS | Publication request: Identification of rice sheath blight QTLs in a Bengal/O. nivara advanced backcross population

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 1, 2009
Publication Date: January 10, 2009
Citation: Prasad, B., Eizenga, G.C. 2009. Identification of rice sheath blight QTLs in a Bengal/O. nivara advanced backcross population. In: Proceedings of Plant and Animal Genome Conference XVII, January 10-14, 2009, San Diego, CA. P. 232.

Technical Abstract: Rice wild relatives contain novel genes for important biotic and abiotic stresses. Rice sheath blight disease, caused by Rhizoctonia solani, is a very important disease of rice worldwide. We screened 67 accessions from 15 Oryza species, and identified seven moderately resistant accessions. Using the advanced backcross method of population development, one can simultaneously identify QTLs and improve germplasm when an adapted variety is the recurrent parent. A mapping population composed of 279 BC2 families was developed between one moderately resistant O. nivara accession and the U.S. medium grain variety, Bengal. The population was phenotyped for sheath blight reaction in the greenhouse (micro-chamber method) and in the field. Sheath blight reaction for the population ranged from moderately resistant to highly susceptible with some progenies being more resistant than the O. nivara parent. The correlation between field reaction and greenhouse tests was significant (r = 0.51**). To identify the QTLs related to sheath blight resistance, 130 SSR markers distributed throughout the rice genome are being used to genotype the population. A linkage map will be developed using JoinMap4 and sheath blight QTLs identified using QGene 4.1. QTLs identified in this population will be compared to known sheath blight QTLs, to determine if a novel gene and/or allele can be identified. Progenies with improved sheath blight resistance will be released to the rice breeding community for use in the development of new cultivars with improved sheath blight resistance. (This research was supported by USDA CSREES NRI RiceCAP.)