Main causes of drying degrade in most plantation-grown eucalypt timber are collapse and checking. Appropriate but costly sawing and drying techniques are employed to alleviate these problems. Eucalyptus globoidea is an emerging plantation species. This study investigated the genetic control of collapse and other tree features in an E. globoidea breeding population established at three different sites. Using a 14-mm diameter corer, thousands of E. globoidea trees representing 163 families were sampled, and genetic parameters for heartwood and sapwood collapse, extractive content, and heartwood diameter were estimated. Heartwood collapse was under genetic control with a narrow sense heritability ranging from 0.22 to 0.44. Considering the coefficient of genetic variability of ∼13–23%, heartwood collapse in E. globoidea can be reduced through selection. The significant genetic correlation between sites for heartwood collapse (r_g = 0.73–0.83) suggested low genotype by environment (G × E) interaction. In line with the physical causes of collapse, heartwood collapse was positively correlated with extractive content. Extractive content and heartwood diameter are other traits of interest, as E. globoidea is grown for its ground-durable heartwood. The heritability of extractive content ranged from 0.40 to 0.71. Heartwood diameter was shown to be negatively correlated to extractive content. No significant genotype by environment (G × E) interaction was found for extractive content while genotype by environment (G × E) interactions for heartwood and sapwood diameter were small. Finally, 12 families had above-average heartwood diameter, extractive content, and below-average heartwood collapse. In summary, this study has shown that genetic selection for collapse and other wood properties of E. globoidea is feasible.

大多数种植园种植的桉树木材干燥退化的主要原因是倒塌和龟裂。采用适当但昂贵的锯切和干燥技术来缓解这些问题。球桉是一种新兴的人工林树种。本研究调查了在三个不同地点建立的E. globoidea繁殖种群中倒塌和其他树木特征的遗传控制。使用 14 毫米直径的取芯器，数以千计的E. globoidea对代表 163 个科的树木进行了采样，并估计了心材和边材塌陷、浸出物含量和心材直径的遗传参数。心材塌陷受遗传控制，狭义遗传力范围为0.22至0.44。考虑到 ~13-23% 的遗传变异系数，可以通过选择减少E. globoidea的心材塌陷。心材塌陷位点之间显着的遗传相关性 ( r _g = 0.73–0.83) 表明环境 (G × E) 相互作用的基因型较低。与坍塌的物理原因一致，心材坍塌与提取物含量呈正相关。提取物含量和心材直径是其他感兴趣的特征，如E. globoidea因其经久耐用的心材而种植。提取物含量的遗传力范围为0.40至0.71。心材直径与提取物含量呈负相关。提取物含量没有发现显着的环境基因型 (G × E) 相互作用，而心材和边材直径的环境基因型 (G × E) 相互作用很小。最后，有 12 个家庭的心材直径、提取物含量高于平均水平，而心材塌陷低于平均水平。总之，这项研究表明，对E. globoidea的塌陷和其他木材特性进行遗传选择是可行的。