西桦组杂种无性系生长、形质变异与早期选择

Growth, Form Variation and Early Selection of Hybrid Clones of Birch in Betula Section Betulaster

以3.5a生西南桦×光皮桦杂种无性系为研究对象,对其胸径、树高、枝下高、冠幅、冠形、干形、分枝等7个性状进行了测定与分析,以期揭示杂种无性系在生长与形质性状上的变异规律,初步筛选优良杂种无性系。结果表明,28个杂种无性系间各性状均差异极显著(p<0.01),其表型变异系数和遗传变异系数分别为20.61%~45.47%和14.26%~29.58%;7个性状的重复力为0.687~0.887,说明这些性状均受较强的遗传控制。无性系的树高、胸径、枝下高、冠幅4个生长性状间以及冠形、干形、分枝度3个形质性状间均呈显著正相关;形质性状与生长性状间多呈显著负相关,其中干形与4个生长性状大多不相关。通过多性状综合评价筛选出A09302、A05201、A07107、A05203、A07119、A07109和A11201共7个优良无性系,其生长和形质性状的遗传增益均在10%以上。本研究结果可为西桦组杂种无性系选育提供信息和依据。

In this research, a clonal test ofBetula alnoidesxB, luminifera hybrids was investigated when three and half years old in terms of stem height, diameter at breast height, crown base height, crown diameter, crown shape, stem form and branchiness, hoping to reveal the genetic variation of in hybrid clones on the growth and quality traits and to select the excellent hybrid clones by comprehensive evaluation. The results showed that remarkable differences existed in each traits among these clones （p〈0.01）, with coefficients of phenotypic variation ranging from 20.61%-45.47%, and coefficients of genetic variation from 14.26%-29.58%. The repeatability of 7 characters was from 0.687 to 0.887, indicating that these traits were subject to strong genetic control. Significant positive correlations were seen among growth traits including stem height, diameter at breast height, under branch height and canopy diameter as well as quality traits such as crown shape, stem form and branchiness. While growth traits were mostly in significantly negative correlation with morphological traits, among which stem form was not remarkably correlated with the four growth traits. Seven superior clones, coded as A09302, A05201, A07107, A05203, A07119, A07109 and A11201 were screened out by comprehensive evaluation of multiple traits, and the genetic gains of their growth and form traits were more than 10%. These findings would provide important information and reference for further hybrid breeding of Betula section Betulaster.