尾叶桉×细叶桉木材密度与生长的联合选择

[目的]评估Resistograph钻刺法间接测定尾叶桉×细叶桉木材密度的可靠性,检测杂交亲本对子代表型的效应以及生长与木材密度的相关,评选速生、优质的尾细桉杂种。[方法]基于10株尾叶桉与10株细叶桉不完全析因交配产生的56个杂交组合的7.5年生试验林,利用79株分析容积法与Resistograph钻刺法测定的木材密度的相关,通过方差分析检测亲本对杂种生长和木材密度的效应,结合多重比较和独立淘汰法进行材积和木材密度的联合选择。[结果]容积法与Resistograph钻刺法测定的木材密度的表型相关系数为0.52(P0.001),遗传相关系数为0.55(P0.05);树高、胸径及材积的母本间和父本间均呈极显著差异(P0.001或0.01),但母本×父本互作的效应不显著;对钻刺木材密度,父本间呈极显著差异(P0.001),母本×父本互作显著(P0.05),但母本间差异不显著;树高、胸径和材积间的表型相关和遗传相关均极显著(P0.001),其与钻刺木材密度的表型相关极显著(P0.001),但遗传相关不显著;评选出速生、木材密度较高的杂交组合14个、单株17株。[结论]Resistograph钻刺法是一种间接测定尾细桉木材密度的简便、经济和可靠的方法;母本和父本选择以及母本与父本的组配对培育速生、材质优良的尾细桉杂种均较重要;尾细桉生长与木材密度的遗传相关不显著,需要对这两类性状分别进行选择;评选的尾细桉杂交组合和单株为培育速生、优质的桉树良种提供了有用的材料。

Combined Selection of Wood Density and Growth in Eucalyptus urophylla×E. tereticornis Hybrids

[Objective] To evaluate the reliability of Resistograph penetration method on indirect measurement of wood density of Eucalyptus urophylla×E. tereticornis hybrids, detect the parental effects on cross phenotypic traits and the correlations between growth and wood density, and select fast-growing and high wood-quality Eucalyptus urophylla×E. tereticornis hybrids. [Method] In a 7.5-year-old trial stand with fifty six hybrid combinations derived from an incomplete factorial mating among 10 E.urophylla (female) and 10 E.tereticornis(male) parents, 79 trees were sampled to determine the correlation in wood density between volumetric and Resistograph measurements. The effects of parents on hybrid growth and wood density were detected by variance analysis. Multiple comparison and independent selection were performed to make joint selection of stand volume and wood density. [Result] The phenotypic and genetic correlation coefficients between volumetric and Resistograph measurements were 0.52 (P<0.001) and 0.55 (P<0.05), respectively. The differences in the traits of height, DBH and stock volume, were highly significant (P<0.001 or 0.01) among either females or males, but no significant difference was observed for female×male interactions. For ResistograPh-based wood density, however, the differences were highly significant (P<0.001) among the males and significant (P<0.05) for female×male interactions, but insignificant among the females. The growth traits of height, DBH and stock volume were highly significantly correlated in both phenotypic and genetic terms (P<0.001), while their phenotypic and genetic correlations with wood density were highly significant (P<0.001) and insignificant, respectively. A total of 14 hybrids and 17 individual trees were selected out. [Conclusion] Resistograph method is convenient, economic and reliable for indirect measurement of wood density of E. urophylla×E. tereticornis hybrids. Female and male parents selecting and parental pairing are important for breeding fast-grow and high wood-quality hybrids. Since there is no significant genetic correlation between growth and wood density, it indicates the necessity of selecting separately against the two traits. The hybrids and trees selected out are of valuable plant materials for further cultivating fast-grow and high wood-quality eucalypt hybrids.