Bursaphelenchus xylophilus virulence in response to increase of Pinus thunbergii resistance

不同无性系对松材线虫的抗性水平不同。抗虫母树插穗接种线虫后成活率高于感虫母树插穗。黑松插穗越短越细，生根能力越强。虽然我选择了不同抗性水平的松树插条和幼苗作为线虫毒力的筛选材料，但松树的抗性水平并不影响所选线虫的毒力。从温州蜜柑仙台市抗性林和感病林中提取的线虫分离物的毒力水平基本相同。

The resistant level against Bursaphelenchus xylophilus was different among P. thunbergii clones. The rooted cuttings from resistant mother trees showed higher survival rate than that from susceptible mother trees after nematode inoculation. The shorter and thinner Pinus thunbergii cuttings tended to show better rooting ability. Although I selected nematode virulence using pine cuttings and seedlings with different resistant level, the resistant level of pines did not affect the virulence of the selected nematodes. Nematode isolates extracted from resistant forest and susceptible forest in Satsumasendai City showed almost the same level of virulence.