白榆优良无性系早期选择的研究

本文以８年生的２４个白榆（ＵｌｍｕｓｐｕｍｉｌａＬｉｎｎ．）杂交无性系为试验材料，进行了白榆生长早期选择的研究。结果表明：不同无性系之间在生长量（胸径、树高、材积）上存在着极显著的差异。通过对白榆历年生长的分析，计算出生长性状间的年一年秩次相关，表明表型相关和遗传相关是极显著的。以胸径、树高、材积等性状的早晚期相关系数建立的回归方程算出的年选择效率表明，从造林后第３年的胸径估计造林后１５年的胸径，造林后３年的胸径和材积估计造林后１２年的材积，均具有极显著的相关性（ｒ＝０．５４９９～０．６６０１）和最高的选择效率（１．２７～２．２７），说明当白榆无性系造林后３年，即４年生时即可根据胸径和材积进行早期选择。

STUDIES ON EARLY SELECTION OF SIBERIAN ELM CLONES

Early selection were studied,based on the measurements of eightyearold test plantation of Siberian elm(Ulmus pumila Linn.).The results were as follows:Siberian elm clones were obviously different in height,diameter and volumer.The juvenilemature correlations of height,diameter and volume were analysed by means of rank correlation.The linear regression equation of the juvenilemature correlation was set up and the annual efficiency at different selection ages was calculated.The results show that the early selection of Siberian elm clones is feasible and the formation of Siberian elm clones is at the age of twelve to fifteen.Therefore,the clonal selection can be made at age of four.