Genetic analysis and gene mapping of rice blast resistance in an indica rice Yuanbaozhan

Rice blast, caused by fungus Magnaporthe grisea, is one of the most serious diseases of rice and has become a serious threat to food security. Yuanbaozhan is a new rice material. Improving the rice resistance to rice blast through genetic improvement methods is the most effective and safe way in the present. Yuanbaozhan has an broad -spectrum resistance to rice blast pathogen, and it has high resistance to 23 strains among 25 blast strains collected from different regions in Guangdong province. Its resistance frequency is 92%. In this study, we made a combination to establish genetic population F1, F2 among which population is from the crosses between Yuanbaozhan and Yuexiangzhan. Evaluation was conducted with Magnaprthe oryzae isolate GD00-193a, the results showed that the resistant and susceptible plants in F2 population fitted the ratio of 3:1, indicating that the resistance of Yuanbaozhan to the rice blast was controlled by a dominant gene or a QTL locus. With the bulked-extrems and recessive-class approach analysis, the rice blast resistance gene was mapped at the genome region between RM136 and RM549.