The resistance of a newly bred line 4163 containing the rice blast resistance gene P/40 and another 11 monogenic lines to rice blast in natural disease nurseries was identified. The results showed that 4163 was resistant to rice blast isolates from Yunnan, and the leaf blast resistance levels were at grades 0, 0 and 4 in Baoshan City, Yiliang City and Yuxi City respectively, while the ear blast resistance was at level 3. Meanwhile, the resistance spectrum of Pi40 to 49 representative rice blast isolates from Yunnan Province was studied by indoor inoculation and was compared with another 25 resistance genes. The results revealed that the resistance frequency of Pi40 to the 49 typical isolates reached 87.8%, showing a broader resistance spectrum, so it could be used as a new source of resistance genes in breeding of japonica rice in Yunnan plateau in the future.
