Research on Inoculation Method and the Inheritance of Resistance to Fusarium oxysporum f.sp. cucumerinum on Cucumber

Fusarium oxysporum f. sp. cucumerinum is one of the most destructive diseases on cucumber (Cucumis sativus L.) throughout China and the world. This experiment was carried out to establish a more reliable screening method and studied on the inheritance of resistance to Fusarium wilt race 4 for resistance breeding of cucumber. The result indicated that the best inoculation method was that seedling roots were dipped into inoculum suspension with 1 × 106 spores/mL when two cotyledons were fully expended,then incubating seedlings at 24-28℃ in daytime,16 - 20℃ at night in greenhouse. Plants are rated as resistant or susceptible 10-14 days after inoculation. The cucumber line WIS2757(parent 1) and the inbred line of Jinyan No. 2(parent 2) and F2 population and 52 F4 lines from the cross of both parents were employed for evaluation of the resistant to Fusarium wilt race 4. Parent WIS2757 plants and F1 plants were resistance to Fusarium wilt race 4,and parent Jinyan No. 2 was susceptible. The segregating ratio of F2 population and F4 lines corresponded with the expected ratio at the 5% level of probability. And the cucumber line Cu13(parent 3) and Jinyu No. 202(parent 4) and F1 lines from the cross of both parents were employed for evaluation of the resistance to Fusarium wilt race 4. Parent Cu13 plants were resistance to Fusarium wilt race 4,parent Jinyu No. 202 was susceptible. F1 plants showed moderate resistance to Fusarium wilt race 4. The above results showed that the resistance of WIS2757 to Fusarium wilt race 4 was controlled by a single dominant gene and the resistance of Cu13 to Fusarium wilt race 4 may be controlled by multiple genes and the further study will be done in the future.