白杨派杂种无性系植株早期性状变异与选择研究

以30个白杨杂种无性系为材料，测定树高、胸径、树形、叶片、树皮特性等17个指标。方差分析与遗传参数计算结果表明，白杨杂种无性系各指标差异极显著（P＜0.001），各指标表型变异系数变化范围为15.63%～57.50%，遗传变异系数变化范围为8.99%～52.57%，重复力高（0.773 4～0.984 8）。说明白杨杂种无性系各性状存在广泛变异,且这种变异受较强的遗传因素控制。表型相关结果表明，白杨杂种无性系树高、地径、胸径、单株材积和冠幅之间均达显著相关水平，遗传相关系数接近表型相关系数。主成分分析结果显示，白杨杂种无性系14个性状前3个主成分的累积贡献率为84.93%，其中第1主成分为生长量等性状，第2主成分为干形等性状，第3主成分为叶片性状。利用综合评定法对无性系进行评价，当入选率为10%时， 无性系BL204、BL206和BL207入选，入选无性系树高、地径、胸径和单株材积的遗传增益分别为27.41%、31.73%、32.90%和102.37%。这些分析结果为下一步选育优良无性系提供了重要的信息和依据。 

Characteristic variation and selection of forepart hybrid clones of Sect.Populus.

A total of 30 white poplar hybrid clones were used to study the phenotypic variation of growth and morphological traits in terms of stem height,diameter,trunk shape,leaf size,and stomata size.Results from the analysis of variance showed that remarkable differences existed in each of the 14 traits measured among these clones(P<0.001),with the coefficients of phenotypic variation ranging from 15.63% to 57.50%,coefficients of genetic variation ranging from 8.99% to 52.57%,and repeatabilities ranging from 0.773 4 to 0.984 8.The analysis of phenotypic correlation showed that there were significant correlations among stem height,diameter,diameter at breast height,and volume per plant.Principal component (PC) analysis showed that the first three PCs explaining growth traits,trunk shape,and leaf traits,respectively,contributed accumulatively 84.93% to the phenotypic variation of the 14 traits.With a selection rate of 10%,BL206,BL207 and BL204 were selected as the best clones.Genetic gains through these three superior clones were 27.41% for height,31.73% for diameter,32.90% for diameter at breast height and 102.37% for stem volume.These results provide important information and basis for white poplar breeding in the next stage.