杨树湘林新无性系不同部位育苗生长性状研究

新、老杨树无性系田间扦插育苗成活率，在湘林～90等5个新无性系与对照中汉-17杨之间有极显著差异，以中汉-17最低；5个杨树湘林新无性系间均无显著差异，可满足大田扦插育苗要求。成活率在苗干区分段问总体上随所取穗条部住的升高而有所下降；但第2、3、4区分段间无显著差异，表明杨树种苗上部的有芽茎干可以用作育苗种条。在夏季无抗旱措施情况下，年末保存率比春季成活率平均有所下降。大田育苗的保存率、成活率与水培时的皮层凸起呈正相关，反映先期根原基多、水培时易形成皮层凸起的无性系及区分段，可以期望有较高的育苗成活率和保存率。成活率、保存率与水培时的发根总长，苗高生长量与水培时的皮层凸起、不定根条数、总长间均没有相关性。试验显示，杨树新无性系扦插繁殖能力的鉴定，最重要、最可靠的程序是通过大田育苗的生产实践来检验。

Studies on growth characteristics of seedling by cuttings from different parts of new Xianglin clones of poplar

As to the survival rate of seedlings of the new and old poplar clones in field cutting, there is a very significant difference between the 5 new Xianglin clones （ Xianglin-90, etc. ） and the control, the Zhonghan-17, which showed with the lowest survival rate. There were no significant differences in seedling cuttings among the 5 new Xianglin clones of poplar, and whieh were suitable for field application. Seedling survival rate was decreased with increasing of positions of cuttings taken over, while, there were no significant differences among cutting from second, third, fourth district. Which showed that poplar seedlings with buds on the top of the stem could be used for seedlings. Without drought-resistance measures in the summer case, the survival rate in end of year was lower than the average survival rate in the spring. The preservation rate, seedling survival rate were positively correlated with number of the breaking out at cortex, implied that the more primordla at the beginning and the number of breaking out at cortex in water culture and parts section, the higher survival rate and breeding preservation rate in the clones. The survival rate, preservation rate had no related with the hair root length in water culture. The seedling height growth had no relations with the number of breaking out at cortex in water culture, or the number of adventitious roots, or length. The results showed that the most important and most reliable procedure for identifieating propagation ability of new clones of poplar cutting is to test by field practice.