[ Objective] The paper was to explore the relationship between SOD activity and resistance of corn against Setosphaeria turcica. [ Method] Strain YC and 01-23T of S. turcica with different pathogenicity were inoculated into corn leaves by fungal disc inoculation method, and the dynamic changes of SOD activity in infected corn leaves was measured. [Result] After inoculation of higly virulent strain YC and weakly virulent strain 01-23T of S. turcica, SOD activity in corn leaves within 1 -5 d showed obvious stages, which gradually decreased within 1 -3 d, then gradually increased within 3 -4 d, and decreased again within 4 -5 d. The SOD activity of corn leaves in inoculation treatment was higher than that in the treatment without inoculation within 1 - 4 d, which significantly decreased at fifth day. The pathogen with different pathogenicity would lead to different changes in SOD activity of corn leaves. SOD activity of corn leaves infected by weakly virulent strain 01-23T for the first day was extremely higher than that infected by strong virulent strain YC, but had no significant difference with highly virulent strain YC at 2 -3 d. [ Conclusion] SOD activity played an important role in initial resistant ability of corn against pathogen infection, and had no significant effect on resistance against pathogen extension after incidence.
