甜瓜對白粉菌Sphaerotheca fuliginea race l抗性之遺傳研究與抗病篩選

Abstract

Leaf disc inoculation method was used to evaluate the resistance of 19 commercial cultivars of Cucumis melo L. to Sphaerotheca fuliginea race 1, the causal agent of powdery mildew in Taiwan. The results showed that 3 of the entries, i.e. Autumn waltz No.2, Chengfang, and Mihua, were resistant, while the rest 16 varieties were susceptible. This indicated that most of the melon cultivars in Taiwan are susceptible to S. fuliginea race 1. The disease reactions of a total of 36 melon inbred lines (S8~S12), developed in our institute, to the same pathogen were also tested by using the same screen method. Among them, 21 inbred lines showed resistant and the other 15 lines were susceptible. In order to understand the inheritance of resistance to S. fuliginea race I in the resistant inbred line 02080(S12) cross hybridization between inbred line 02080 and a susceptible inbred line 02077(S9) was conducted. The parents (P1 and P2) and their progenies, including F1, F2, BC(subscript R), and BC(subscript S), were inoculated and the disease response in each individual plant was recorded and analyzed. The segregation ratios of resistance vs. susceptibility obtained from this experiment indicated that the resistance trait seems being under the control of a single dominant gene.