鹅掌楸种源材性遗传变异与选择

在鹅掌楸两个种及其杂种多地点７年生种源试验林中,随机抽取３块试验林共２８２株样本,分别遗行木材基本密度（ＢＤ）和纤维长度（ＦＬ）的测定分析,在分布型拟合与精度分析的基础上,进行一般线性方差模型分析,结果为：中国鹅掌楸种源间ＢＤ和ＦＬ均差异显著（a=0.05),５个北美鹅掌楸种源间ＢＤ和ＦＬ未达到显著差异,地点间差异及种源与地点的交互作用不显著,平均值Ｔ检测表明中国掌楸与北美鹅掌楸两种间ＢＤ和ＦＬ均不存在显著差异,鹅掌楸的ＢＤ总均值为0.397g/cm^3,ＦＬ总均值达１.603mm,属于中小密度,长纤维或近长纤维树种,差异分析揭示了种内差异是掌释属的主要变异来源,种内种源间存在选择的遗传基础,性状遗传相关分析认为,鹅掌楸ＢＤ和ＦＬ之间相互不密切（r=0.157),两本材料状与各生长因子间相关亦不密切,说明他们之间基因连锁不紧密,可独立选择。BD种源广义遗传力为H^2BD=0.65,受遗传控制较强,ＦＬ为Ｈ^FL=0.29,受遗传控制中偏弱,两性状年－年间遗传相关密切,在上述分析结果的基础上方３种标准进行了鹅掌楸属材料种源选择,其中,在“强度选择”条件下,选出ＢＤ优良的种源为庐山和桑植,ＦＬ优良的种源为浏阳和赣武夷,均为中国掌楸种源,北美种源虽然与中国种源在总体上不存在明显差异,但多数处于中等水平上,对照杂种夫性系ＢＤ和ＦＬ的均超过鹅掌楸性状总均值,但未超过最好的种源。

STUDY ON GENETIC VARIATION AND SELECTION OF MAIN WOOD CHARACTERISTICS AMONG PROVENANCES OF LIRIODENDRON

Measurement and analysis of wood basic density (BD) and fiber length (FL) of 282 wood cores, which sampled from seven year-old provenance plantations of two species of Liriodendron, Chinese Tuliptree ( Liriodendron chinense ( Hemsl. ) Sarg) and Tuliptree ( Liriodendron tulipifera L. ), in Jiangxi, Fujian and Hubei province respectively, were conducted. The samples were divided into groups and the frequency of each group was counted and normally imitated. The result showed that the wood core samples were abided by the normal distribution at two characteristics. The precision analysis showed that the 6 trees sampled from each provenance were of higher precision ( P＞90% ) ,and 1～2 trees sampled from each provenance were of lower precision ( P＜80% ) which could not be taken in the variance analysis but only used for calculating the average of provenance. T-test proved that there were not significant differences in the BD and FL between Chinese Tuliptree and Tuliptree. The BD and FL average of Liriodendron, including Chinese Tuliptree and Tuliptree, was 0.397 g/cm3 and 1.603 mm, respectively. Liriodendron was the species with long-fiber and middle-low-density according to wood classification criterion by cheng Junqing. The variance analysis indicated that the differeneces of BD and FL Among provenances in Chinese Tuliptree were both significant at 0.05 level, and those of Tuliptree were not significant. The difference among sites and the mutual actions of G (provenances) and E(sites) were both not significant. BD's hereditability in broad sense was 0.654 and Fl's was 0.29, which indicated that BD was strongly controlled by genetic factors, while FL was weakly controlled by genetic factors. Characteristic coorrelation between BD and FL was very weak (r=0.157) and relationship between BD, FL and growth traits was also very weak, which impressed the independent selection of each characteristics could be conducted. Age-age genetic correlations of BD and FL were analyzed and all age-age correlation coefficients only except that one between 1 a and 5 a were significantly at 0.05 level. At the base of the analysis above, the provenance selection of wood character combined two species in Liriodendron was conducted according to different selection criteria so that the selection results could meet the different breeding demands. The results showed the most excellent provenances of WD were Lushan in Jiangxi Province and Sangzhi in Hunan Province, and the most excellent provenances of FL were Liuyang in Hunan Province and Ganwuyi in Jiangxi Province. Although the hybrid clones (CK) were beyond the average, it did not reach at the top provenance. The tuliptree provenances were not selected as the excellent provenance becuase they were slightly varied around the average line.