CHARACTERISTICS FOR THE SELECTION OF PARENTS OF Corymbia citriodora AIMING TO THE PRODUCTION OF WOOD AND ESSENTIAL OIL

ABSTRACT This study aimed to identify the most important characteristics for the selection of parent trees of Corymbia citriodora by estimating genetic dissimilarity and linear correlation degree for wood and essential oil production. This study was conducted in experimental areas of the company JAMP Florestal -located in Dueré-TO -and at Universidade Federal do Tocantins (Federal University of Tocantins), campus Gurupi, from January to April 2014, in 19 parent trees based on 19 characteristics. With the data, the following steps were performed: clustering through Tocher’s optimization method; calculation of genetic dissimilarity between parents; quantification of relative contribution; and verification of correlation degree existing among the characteristics evaluated through Pearson correlation using the program GENES. The characteristics essential oil yield and heartwood diameter presented the major contributions for genetic dissimilarity. Thus, it must be prioritized for wood production: trees with lower values in crown height and sapwood diameter; and trees with higher values in total height, commercial height, diameter at breast height and stump diameter. For essential oil production, it must be prioritized trees with lower values in leaf width, bark thickness and sapwood diameter; and trees with higher values in leaf nitrogen content, leaf potassium content, total green biomass and total dry biomass, essential oil yield, essential oil content and crown volume.

摘要 本研究旨在通过估算林木遗传差异度与木材、精油产量的线性相关程度，确定柠檬桉（Corymbia citriodora）母树选择的关键性状。本研究于2014年1月至4月在两处开展试验：一处为位于托坎廷斯州杜雷（Dueré-TO）的JAMP Florestal公司试验林，另一处为托坎廷斯联邦大学（Universidade Federal do Tocantins）古鲁皮校区，共选取19株母树，测定19个相关性状。基于采集的数据，本研究完成以下分析流程：采用Tocher优化法进行聚类分析；计算母树间的遗传差异度；量化各性状的相对贡献；并通过GENES软件开展皮尔逊相关分析，以验证各测定性状间的相关程度。研究结果表明，精油产量与心材直径对遗传差异度的贡献最大。据此，木材选育需优先选择冠高较低、边材直径较小，且总树高、商品材高度、胸径、伐桩直径较高的单株；而精油选育则需优先选择叶宽、树皮厚度、边材直径较低，且叶氮含量、叶钾含量、总绿色生物量、总干生物量、精油产量、精油含量及冠幅体积较高的单株。