<正>本文以年遗传增益(△G_t)和期望遗传增益(G_t)为评定尺度,分别讨论了Ⅰ-69杨×小叶杨和Ⅰ-69杨×欧洲黑杨F_1无性系树高、胸径和材积的最佳选择年龄(x_(max)),利用聚类分析的方法对早期选择效果的稳定性进行了检验。Ⅰ-69杨×小叶杨F_1无性系的早期选择年龄可早至定植后2年 (包括定植年龄),Ⅰ-69杨×欧洲黑杨F_1无性系早期选择年龄在定植后3年(不包括定植年龄)。在这些年龄对无性系进行的选择能够代表轮伐年龄的选择,并且选择的遗传增益将达到最大。研究结果表明,黑杨派新无性系的早期选择是有效的。

This paper discussed the optimum selection ages(xmax) of height, diameter and volume in 1-69 poplar x Simon poplar and 1-69 poplar x Nigra poplar F1 clones, using annual genetic gain(△Gt) and expected genetic gain(Gt) as the evaluation criteria, and the stability of their early selection result was tested. Age of early selection might be as ealy as 2 years after plantation(not including plantation age) in 1-69 poplar x Simon poplar Ft clones. Age of early selection was 3~4 years after plantation(including plantation age) in 1-69 poplar x Nigra poplar F, clones. Selection for these two F1 clones at these ages would represent that at rotation ages, and genetic gain of the selection would achieve the maximum value. Therefore, it was concluded that early selection would be effective.