湿地松、火炬松种源抗褐斑病试验和抗病优树选择

<正>用人工接种的方法比较国内的八个湿地松种源对松针褐斑病的感病性的结果表明,不同湿地松种源间感病性有差别,但没有达到可以利用它们进行病害防治的程度。自然感染的美国七个湿地松种源和十个火炬松种源也都表现高度感病。湿地松,黑松和火炬松是高度感病的树种,短叶松、长叶松和沙松感病中等,马尾松是高度抗病的。在松针褐斑病流行的湿地松幼林中选择了47株抗病优树,用自然感染法对各优树无性系的感病性测定表明,约有1/2的优树无性系是高度抗病的。

RESISTANCE TO BROWN SPOT DISEASE OF GEOGRAPHIC SEED SOURCES OF SLASH PINE AND LOBLOLLY PINE AND SELECTION OF RESISTANT PHENOTYPES OF SLASH PINE INDIVIDUAL TREES

Disease resistance to brown-spot needle blight of 7 geographic seed sources of slash pine and 10 of loblolly pine from USA was tested by planting 1~2 years old seedlings of these seed sources nearby a slash pine plantation which had been destroyed by brown-spot disease. The results showed that all the seed sources tested are highly susceptible to the disease although there are certain differences among them. 1~2 years old seedlings of 8 seed sources of slash pine from several provinces in south China were tested by artificial inoculation with brown-spot fungus in nursery and the same result was obtained. The parent slash pine stands of these seed sources were established in 1930s and 1940s respectively with exotic seeds. In severely infected slash pine plantations, slightly infected or non-infected individual trees are commonly detected. These resistant phenotypes are probably due to inheritence. In 1982, 47 brown-spot disease resistant slash pine trees were selected from Fujian and propagated by grafting on stocks of 4-years old slash pine and loblolly pine which were moderately infected by brown-spot disease. After 3 growing seasons, most stock trees were severely infected, but there were 21 of 47 clones of slash pine out of infection or slightly infected.