Original article Genetic parameters for lignin, extractives and decay in Eucalyptus globulus

Abstract – Eucalyptus globulus is grown in temperate regions of the world for pulp production. The chemical and physical properties of its wood make it highly suited to this purpose. This study analysed genetic variation in lignin content, extractives content and decay, for nine localities of E. globulus. Heritability estimates were also obtained, and the relationships between these traits and physical wood traits and growth were examined. Significant genetic variation was found between localities for lignin content (Klason lignin and acid-soluble lignin contents) and decay. The only trait for which significant variation between families within locality was detected was acid-soluble lignin content, which resulted in this trait also having the highest narrow-sense heritability (0.51 ± 0.26). However, family means heritabilities were high for lignin content, extractives content and decay (0.42–0.64). The chemical wood traits were strongly correlated with each other both phenotypically and genetically, with important correlations found with density and microfibril angle. Correlations suggested that during selection for the breeding objective traits, it is likely that favourable states in the chemical wood traits, decay resistance and fibre properties are concurrently being selected, whereas growth may be selected for independently. This initial study provides a stepping stone for future studies where particular localities of the breeding population may be characterised further