<正>本文分别讨论了Ⅰ-69杨×小叶杨和Ⅰ-69杨×欧洲黑杨F_1无性系树冠结构各组成部分与生长的表型和遗传相关;利用通径分析具体剖析这种相关的直接和间接作用,确立不同F_1无性系的理想冠型;并据此计算生长选择指数,比较各种性状组合的选择效果。利用一个最合理的选择指数式对各无性系的生长进行预测,结果表明,通过苗期测定选出的几个优良无性系之所以能保持速生特性,是因为具有较为合理的树冠结构。

This paper analysed the phenotypic and genotypic correlations of the different component parts of the tree crown structure to the growth in the two various systems of Ⅰ-69 poplar × Simon poplar and Ⅰ-69 poplar x Nigra poplar F1 clones, separately, the correlations were coneretely analysed into the direct effects and indirect effects by path-analysis, the ideal crown forms of the various systems were determined, the selection indexes of the growth were computed on the basis above, and the selection results of various character combinations were compared. The growth estimates of the different clones were taken by means of the most reasonable equations of selection indexes, which indicated preliminarily that the several good clones selected during nursery could maintain the rapid-growing properties, because they had reasonable relately tree crown structures.