An Overview of Rice QTLs Associated with Disease Resistance to Three Major Rice Diseases: Blast, Sheath Blight, and Bacterial Panicle Blight

Rice (Oryza sativa L.) is one of the most important crops that are produced as human food, directly feeding people more than any other crop. Hence, it is important to increase the yield potential of rice through improving the disease resistance to prevailing rice diseases. Blast caused by the fungus Magnaporthe oryzae, sheath blight caused by the fungus Rhizoctonia solani Kuhn, and bacterial panicle blight caused by the bacteria Burkholderia glumae and B. gladioli are serious rice diseases in many rice-producing regions. In spite of the chronic damages from these major diseases, the quantitative resistance to each of them is not known very well and any available disease-resistant varieties are rare or not stable. Although gene-for-gene resistance that is mediated by an R-Avr interaction has been intensively studied for blast, quantitative (or horizontal) resistance to a broad spectrum of races in M. oryzae is still poorly understood. Identification of the quantitative trait loci (QTLs) related to these diseases and using marker technology can facilitate marker-assisted selection to screen resistant traits in individual resources, which could ultimately lead to the development of novel disease-resistant rice varieties. This article is a summary of identified QTLs that are associated with rice diseases, including blast, sheath blight, and bacterial panicle blight that can be used in breeding programs.