**Submitted to:** Crop Protection

**Publication Type:** Peer Reviewed Journal

**Publication Acceptance Date:** 11/19/2012

**Publication Date:** 3/11/2013

**Citation:** Wang, J., Jia, Y., Wen, J., Liu, W., Liu, X., Li, L., Jiang, Z., Zhang, J., Guo, X., Ren, J. 2013. Identification of rice blast resistance genes using international monogenic differentials. Crop Protection. 45:109-116.

**Interpretive Summary:** Rice blast disease is the single most destructive disease in Jilin, a province in northeastern China. In the present study, 44 blast isolates were identified that represent the diversity found within the pathogen population in this province. A set of monogenic lines carrying 24 major blast resistance genes Pi-a, Pi-b, Pi-i, Pi-k, Pi-kh, Pi-km, Pi-kp, Pi-ks, Pi-sh, Pi-t, Pi-ta, Pi-ta2, Pi-z, Pi-zt, Pi-1 , Pi-z5, Pi-3, Pi-5(t), Pi-7(t),Pi-9, Pi-l2(t), Pi-11(t), Pi-19, and Pi-20 in the susceptible rice cultivar Lijiangxintuanheigu (LTH) that was developed by International Rice Research Institute, the Philippines, was used to determine which genes provide resistance to the spectrum of rice field pathotypes. The monogenic lines carrying Pi-9, Pi-19, Pi-z, Pi-z5, Pi-zt, Pi-12(t), Pi-5(t) and Pi-kh were found to be resistant to 68.2 to 94.2 percent of the 44 tested isolates. It was found that Pi-9 plus one or two other resistance genes would be effective in preventing blast disease in most rice producing counties of Jilin province.

**Technical Abstract:** Rice blast disease, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating diseases of rice that severely affects crop production in Jilin Province, Northeast China, where temperate japonica rice is primarily grown. In the present study, 44 representative local blast isolates were inoculated onto an international set of monogenic differentials carrying 24 major blast resistance genes: Pi-a, Pi-b, Pi-i, Pi-k, Pi-kh, Pi-km, Pi-kp, Pi-ks, Pi-sh, Pi-t, Pi-ta, Pi-ta2, Pi-z, Pi-zt, Pi-1 , Pi-z5, Pi-3, Pi-5(t), Pi-7(t),Pi-9, Pi-l2(t), Pi-11(t), Pi-19, and Pi-20 in the susceptible recurrent parent Lijiangxintuanheigu (LTH) under greenhouse conditions. It was found that all isolates were virulent on some monogenic lines. The LTH variety was susceptible to all 44 isolates, and all 24 monogenic lines were resistant to at least 4 isolates of M. oryzae. The monogenic lines ranged 8.3 to 79.2 percent in virulent reactions to the 44 isolates. The frequency of resistant reactions of the monogenic lines carrying Pi-9, Pi-19, Pi-z, Pi-z5, Pi-zt, Pi-12(t), Pi-5(t) and Pi-kh were 94.2%, 84.1%, 81.8%, 81.8%, 79.5%, 72.7%, 68.2% and 68.2%, respectively. These results suggest that Pi-9, Pi-19, Pi-z, Pi-z5, Pi-zt, Pi-12(t), Pi-5(t) and Pi-kh may be important for preventing blast disease in Jilin province.