桉树无性系木材基本密度和树皮率遗传变异分析

Variation of Basic Density and Stem Bark Among Eucalyptus Clones

分析不同桉树无性系间胸径、木材基本密度、树皮密度、树皮率的差异性,以及不同树干高度间木材基本密度、树皮密度、树皮率的变化,掌握其变异规律,以期为优良无性系选育与木材和树皮利用提供科学依据。以林龄为6 a的12个桉树无性系为材料,分析胸径、木材基本密度、树皮密度、树皮率的差异性,估算遗传参数及遗传相关系数。结果表明:胸径、木材基本密度、树皮密度、体积树皮率、质量树皮率不同无性系间及木材基本密度、树皮密度、体积树皮率、质量树皮率、不同树干高度间差异均极显著。木材基本密度无性系重复力和单株重复力均最大,为0.98和0.95,质量树皮率无性系重复力和单株重复力均最小,为0.75和0.43;遗传变异系数变化范围为8.03%(木材基本密度)~9.68%(质量树皮率)。木材基本密度与质量树皮率呈极显著遗传负相关,树皮密度与体积树皮率呈极显著遗传负相关。木材基本密度、树皮密度在树干高度的变化无明显规律,体积树皮率、质量树皮率呈U型变化。5个性状不同无性间差异显著,可根据不同培育目标选择合适的无性系;无性系3号生长量和木材基本密度均较大,可应用于优质纸浆材培育。

Variation among a range of Eucalyptus clones for variation in DBH,basic density,bark density and bark rate was investigated along with their variation for wood basic density,bark density and bark rate at different stem heights,in order to provide a scientific basis for utilization of stem wood and bark,and also to select excellent clones.Six-year-old trees of 12 Eucalyptus clones were assessed and the data obtained were analysed to provide genetic parameters and genetic correlations.Results showed that,the differences among clones for DBH,basic density,bark density,volume bark rate and quality bark rate were highly significant,and basic density,bark density,volume bark rate and quality bark rate also varied significantly with stem height.Wood basic density had the highest clonal heritability and individual heritability of all traits assessed at 0.98 and 0.95 respectively,while quality bark rate had the lowest heritabilities at 0.75 and 0.43 respectively.The genetic variation coefficients ranged from 8.03%(basic density)to 9.68%(quality bark rate).The genetic correlation of basic density with quality bark rate showed a highly significant negative correlation and bark density with volume bark rate showed a significant negative correlation.There were no clear trends for the variation in either basic density or bark density with stem height,whilst bark volume rate and bark rate quality showed a‘U trend’with stem height.The best clone could be selected according to different cultivation objectives;and for pulpwood production clone 3 was selected for having excellent DBH and basic density.