Abstract:In the present study, the authors studied the interaction between 26 monogenic differentials carrying 26 blast resistance genes with 15 isolates of Pyricularia oryzae under field conditions and pathogenicity assays. The result in field conditions showed that area under disease progress curves (AUDPC) of monogenic lines was found to range from 0 to 142.3. Lijiangxintuanheigu (LTH) was susceptible in all of regions. The monogenic lines carrying Pik, Piz, Pi1, Pi7(t), Pi4(t), Pish, Pi9(t) and Pita were highly resistant to blast in all of regions. In plastic house net conditions, the percentage of virulent reactions of monogenic lines to 15 isolates was found to range from 23.1% to 84.6%. LTH was susceptible to all 15 isolates. All 26 monogenic lines were resistant to at least 3 isolates of P. oryzae, and the frequency of resistant reactions of the monogenic lines carrying Pik, Piz, Pi4(t), Pish, Pi1, Pi7(t), Pi9, Pik-m and Pita were 80.0%, 93.3%, 93.3%, 80.0%, 73.3%, 86.7%, 73.3%, 80.0%, 80.0%, 80.0% and 80.0%, respectively. These findings suggest that Pik, Piz, Pi4(t), Pish, Pi1, Pi7(t), Pi9, Pik-m and Pita may be important R genes for preventing blast disease in South Central Vietnam. Based on these data, a useful strategy for managing rice blast disease by stacking pyramiding blast R genes against pathogenic P. oryzae isolates at hotspot in South Central Coast of Vietnam was proposed.