Classification of Eucalyptus clones by the ratio syringyl/guaiacyl and growth characteristics for energy use

Abstract

The objective of this study was to determine the feasibility of using the ratio syringyl/guaiacyl of lignin and dry matter productivity in the classification of Eucalyptus clones, in order to generate heat and for charcoal production, using univariate and multivariate techniques. 39 Eucalyptus spp. clones were evaluated at 81 months of age, and three trees were sampled per genetic material. All trees were accurately scaled for obtaining of the individual volume. For the classification and grouping of Eucalyptus clones, the following characteristics were used: Basic density, total lignin content, ratio syringyl/guaiacyl (S/G), individual volume under bark and estimates of wood dry matter, carbon and total lignin. Univariate analyses of variance were performed and, for clone grouping, the Scott-Knott algorithm at 5% significance was used. Multivariate cluster analysis was also used, in order to obtain groups of similar clones. It was observed that wood dry matter and carbon estimates were the variables that most contributed to the total genetic divergence, being decisive in the grouping and classification of Eucalyptus clones for energy purposes. The content of total lignin, ratio S/G and matter estimate of lignin little contributed to the genetic diversity of the analyzed materials. However, they should not be overlooked in clone ranking for charcoal or thermal energy production.