Mapping of the quantitative trait locus (QTL) conferring resistance to rice false smut disease

Rice false smut disease, caused by Ustilaginoidea virens, is an important grain disease in rice production worldwide. An F-2 population of 176 plants was used to conduct quantitative trait locus (QTL) mapping for rice false smut disease resistance. A total of 360 simple sequence repeat (SSR) markers were screened for polymorphism on the parents, susceptible and resistant bulks, which yielded SSR markers linked to false smut disease resistance gene. Bulk segregant analysis located the resistance gene to chromosome 5. QTL analysis also identified two QTLs on chromosome 5, the phenotypic variations explained by these two QTLs are 7.3% and 16.4%. The qRFSr-5.1 was about 0.8 centimorgans (cM) to SSR marker RM18451 accounting for 7.3% of phenotypic variation, and qRFSr-5.2 about 1.1 cM to SSR marker M72 accounting for 16.4%. The SSR markers linked to rice false smut disease resistance genes can be used for marker-assisted selection and also they serve as landmarks for cloning false smut disease resistance genes in the future.