Pathogenicity Analysis on Magnaporthe oryzae from Hybrid Combination Wuyou 308

Eighteen blast isolates were obtained from hybrid combination Wuyou308 using the Magnaporthe oryzae pathogen isolation method.Race identification of these isolates was conducted based on seven Chinese blast differentials and 11 blast monogenic lines.The results indicated that the isolates were identified as the races of ZB13,ZB15 and ZC13,accounting for 66.67%,27.78%,5.56%,respectively,and the resistance genes including Pi-ta2 and Pi-sh,Pi-i were highly susceptible to these isolates,while the resistance genes like Pi-kh,Pi-1,Pi2,Pi-9 and Pi-50 showed good resistance to tested pathogens.All isolates were compatible to the original rice hybrid Wuyou308.Three isolates including GDHY-308-1401 were used for testing their pathogenicity to 45 local varieties.The results demonstrated that 13 varieties appeared highly susceptible to the tested isolates,accounting for 28.89%;two varieties appeared moderately susceptible to the tested isolates,accounting for 4.44%;30 varieties showed moderately/highly resistance,accounting for 66.67%.Among them,some of new hybrid combinations such as Wufengyou 9802,Wuyou 613,Wuyou 1179 showed good resistance to the inoculated strains,and they were recommended to be candidates in the rice region where Wuyou308 showed susceptibility.