ARS | Publication request: Allelic analysis of sheath blight resistance with association mapping in rice

Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2012
Publication Date: March 13, 2012
Citation: Jia, L., Yan, W., Zhu, C., Agrama, H.A., Jackson, A.K., Yeater, K.M., Li, X., Huang, B., Hu, B., McClung, A.M., Wu, D. 2012. Allelic analysis of sheath blight resistance with association mapping in rice. PloS One 7(3):Article e32703.

Interpretive Summary: Sheath blight is one of the most devastating diseases world-wide in rice. Genetic improvement of this staple food crop can serve as a major component of sustainable production. Due to the high cost of cultural practices and the phytotoxic influence associated with the application of fungicides, the use of sheath blight resistant cultivars is considered the most economical and environmentally sound strategy in managing this disease. For the first time, we adopted association mapping to identify quantitative trait loci for sheath blight resistance from the USDA rice mini-core collection. Ten marker loci were identified to be significantly associated with response to sheath blight, of which two were novel. We conducted allelic analysis for the ten markers that are associated with sheath blight resistance, and demonstrated that pyramiding resistant alleles should be an effective strategy to improve cultivar resistance. These findings show the potential to improve breeding efficiency by using marker assisted selection.

Technical Abstract: Sheath blight is one of the most devastating diseases world-wide in rice. For the first time, we adopted association mapping to identify quantitative trait loci for sheath blight resistance from the USDA rice mini-core collection. The phenotyping was conducted with a newly developed micro-chamber method and genotyping was performed with 155 genome-wide molecular markers. Ten marker loci were significantly associated with response to sheath blight, of which two were novel. The number of resistant alleles, defined as the most resistant allele at each locus, was significantly correlated with sheath blight resistance (r=-0.535). Entry GSOR 310389 had the most resistant alleles and had greater resistance than the resistant check cultivar. The Indica sub-population contained more resistant alleles than japonica germplasm. These findings will help improve breeding efficiency for sheath blight resistance with marker-assisted selection on an allelic level.