香椿无性系苗期生长及早期选择研究

目的]对香椿无性系的苗期生长进行分析,筛选优良香椿无性系,奠定遗传改良的基础。方法]以49个香椿无性系为对象,分别于2015、2016、2017年测量其1、2、3 a生株高、胸径,计算材积,对表型性状及其增长量进行方差分析和遗传参数估算,采用独立淘汰法筛选排名前20%的无性系为优良,对中选无性系进行遗传增益等参数估算,并将试验地不同年份特征气象因子与无性系表型性状进行相关分析。结果]株高、胸径及材积的生长连续3 a在无性系间存在显著差异,且生长性状的遗传变异系数、表型变异系数逐年减小,而变异幅度、重复力逐年增大;3 a生时,株高、胸径及材积的无性系重复力分别为0.55、0.50、0.67,重复力高。2015—2017年,49个香椿无性系之间胸径、材积增长量分别呈显著、极显著差异,3 a生材积与材积、胸径增长量呈高度正相关关系。以3 a生香椿无性系材积及其增长量为2组指标,独立筛选出优良无性系10个,中选无性系群体平均材积大于0.010 4 m~3·株~(-1),增长量大于0.009 7 m~3·株~(-1)。3 a生材积的遗传增益为17.38%,中选香椿无性系的稳定性系数b值均大于1,对年份环境敏感。气象因子-表型性状相关性分析显示,材积与年总降水量、日均降水量有显著正相关关系。结论]参试香椿无性系间材积差异极显著,选择潜力大;中选的优良香椿无性系遗传增益超过15%,但其在不同年份差异大且稳定性差,这可能与年份降水量有关。

Study on Growth Traits of Different Toona sinensis Clones and Superior Clone Early Selection

Objective] In order to screening for superior clones and laying the foundation for the genetic improvement of Toona sinensis, the grafting seedling growth of 49 T. sinensis were evaluated.Method] The plant height and DBH of 49 T. sinensis clones with the age of 1, 2, and 3 years were measured in 2015, 2016, 2017, respectively. The volume was calculated. Variance analysis and genetic parameter estimation were used to estimate the phenotypic characters and their growth. The top 20% of the clones were selected by independent elimination method. The genetic gains of the selected clones were estimated, and the correlation between characteristic meteorological factors and the phenotypic traits of the tested clones were analyzed.Result] There were significant differences in the height, DBH and volume of T. sinensis clones in the continuous 3 years. The genetic variation coefficient and phenotypic variation coefficient of the 3 growth traits showed a decreasing trend, while the variation range and the repeatability (R) increased year by year. The repeatabilities of height, DBH and volume of T. sinensis clones reached the highest point at the third year, which were 0.55, 0.50, and 0.67, respectively. The DBH and volume growth showed significant and highly significant differences among clones from 2015 to 2017. There was a highly positive correlation between volume with the growth of volume and DBH. According to the volume of 3-year-old clones and their growth, 10 superior clones were screened out. The average volume of the selected clones was greater than 0.010 4 m³, and the growth was greater than 0.009 7 m³. The genetic gain of the 3-year-old biomass was 17.38%. And the coefficient of stability (b) value of the selected clones was greater than 1, showing that the selected clones were sensitive to the environmental change. The correlation analysis of meteorological factors-phenotypic traits showed that the volume had a significant positive correlation with total annual precipitation and average daily precipitation.Conclusion] The difference in volume between the tested clones is extremely significant, which demonstrates a large selection potential. The genetic gain of the selected clones is high, but it is different among years and the stability is poor, which might be related to the annual precipitation.