杨树对杨干象抗性选择的研究

在杨干象危害80％以上的人工杨树林内,以抗杨干象、速生等综合指标,选出了抗虫优树。对3年生优树后代室内外人工接种和自然感染的结果表明:106号优树比周围3株优势水平均胸径高9％,树高高7％,材积高61％,室内接种其诱虫数、取食孔数都低;野外接种,虫株率低40％以上,危害指数低69％;自然感染的虫株率低54％,危害指数低50％以上。优树生长量较对照原种中东杨(Populus berolinensis)高得多,但低于小黑杨(P.×xiaohei)。其抗虫性与树皮内含物果糖和酚酸含量有关。

Study on the Selection of Poplar Resistance to Cryptorrhynchus lapathi

In artificial seedling wood of poplar, Cryptorrhynchus lapathi Linne is a serious insect pest. Study was conducted in the plantation,where the damaged plant rate was over 80%. The aim was to select fine trees which were mainly resistant to C. lapathi and combined with the comprehensive target of fast-growing and high-yield. In laboratory, artificial inoculation and natural infection were carried out for the 3-year-old generation of the fine trees. The results showed that the diameter, height and volume of the selected fine tree No. 106 was 9 %, 7 % and 61 % bigger or higher than the average of those of the 3 surrounding trees respectivly. As to the artificial inoculation for the 3-year-old generation, the attracted no. of insects and feeding holes in the branches of No. 106 were lesser. As to the artificial inoculation in the field, the tree-with-insect rate of No. 106 was 40 % lower than that of the check, and the damage index 69 % lower than that of the check. As to the natural infection, the tree-with-insect rate of No. 106 was 54% lower than that of the check, and damage index over 50% lower than that of the check. The volume-growth of No. 106 was much more than that of its original species, Populus berolinensis Dipp., but lower than that of P. xiaohei T. S. Hwang, et Liang. According to the analysis of its bark, it's considered that the resistance of the tree was related to the amount of the content of fructose and phenolic acid.