尾叶桉×细叶桉杂种无性系扦插生根和生长性状的研究

Analysis on Cutting and Growth Traits of Clones of Eucalyptus urophylla×E.tereticornis

对尾叶桉×细叶桉5个杂种组合的181个无性系扦插生根和生长性状的研究表明：每穗根数、每穗最长根长和生根率3个扦插生根性状，杂种组合间和杂种组合内无性系间的差异均达0．01显著水平；46个月生树高、胸径和单株材积3个生长性状，杂种组合问差异不显著，杂种组合内无性系间的差异达0．01显著水平。无性系扦插生根性状和生长性状的广义遗传力介于0．32（每穗最长根长）～0．94（生根率）之间，表明各性状受中等到高等程度的遗传控制。无性系扦插生根性状平均值与生长性状平均值的表型相关均不显著。无性系各生长性状在13、18、46个月生之间的年年相关均达到0．01显著水平，表明在较早生长期进行无性系选择具有一定的可行性。本研究初选出易扦插、速生的尾细桉杂种无性系24个，无性系间单株材积株间变异系数为13．87％～68．55％，无性系内变异可能与母株年龄效应、位置效应和立地环境条件等C-效应因子有关。对桉树杂交育种而言，杂交制种后直接进行育苗、扦插和无性系试验是一条快捷有效的无性系培育途径。

This paper presented the analysis on cutting and growth traits of 181 clones representing five E. urophylla S. T. Blake × E. tereticornis Smith hybrids. The hybrids and the clones within hybrid differed in all three cutting traits, number of roots per cutting （RN）, the maximum root length per cutting （RL）, and rooting percentage per plot （RP）, at 0.01 significance level. For the three growth traits, height （H）, diameter at breast height （D）, and volume （V）, the clones within hybrid differed at 0.01 significant level when 46 months old, while the hybrids showed non-significant difference The broad-sense heritability ranged from 0.32 to 0.94, implying moderate to high genetic control of the traits studied. No significant correlation was found between cutting traits and growth traits though either cutting traits or growth traits showed significant correlations （p 〈0.01 ）. Age-age correlations between 13, 18, and 46 months were significant at 0.01 level in all the growth traits, indicating the availability of clone selection at a relatively early age. Twenty-four superior clones were selected for further pilot trials basing on their performance in cutting and growth traits. It is efficient in eucalypt breeding to carry out clone test with cuttings raised directly from hybrid seed.