Identification and Selection of Fresh Corn Germplasm Resources with Resistance to Southern Corn Rust

Objective The resistance of fresh corn germplasm resources to southern corn rust was explored with a view to provide materials and theoretical references for resistant varieties.

Method Investigation was conducted to analyze the resistance of different inbred lines to southern corn rust with the method of visual observation under field natural conditions and artificial inoculation.

Result There were significant differences between different inbred lines of fresh corn. Under field natural conditions, only 1.11% of 710 tested inbred lines showed highly resistant level, and 8.34% of which showed resistant level. About 77.75% of inbred lines showed middle resistant and susceptible levels, while the rest showed highly susceptible level. After artificial inoculation, 5 inbred lines of fresh corn that highly resistant to the southern corn rust were screened out, including three of waxy corn, one of sweet corn and one of waxy-sweet corn. Preliminary genetic analysis of the resistant inbred line 09N1-1-1 showed that the separation ratios of F₂ and BC₁F₁ populations were 3 ∶ 1(χ²=2.473, P=0.116)and 1 ∶ 1(χ²=0.084, P=0.772)respectively, revealing the resistance of inbred line 09N1-1-1 was probably controlled by a single dominant gene.

Conclusion The study demonstrated that the current fresh corn resources have high resistance to southern corn rust. Therefore, the selection and utilization of disease resistant germplasm has potential application in variety breeding currently.