Chemical properties of wood are under stronger genetic control than growth traits in Populus tomentosa Carr.

Abstract

The genetic development of some wood quality characteristics in early stage is particularly attractive since these properties are generally inherited. A clear understanding of the genetic control of chemical properties of wood (extractives, holocellulose, and lignin content) and growth traits (tree height, diameter at breast height, and stem volume) of corewood is a prerequisite for breeding for higher wood quality in triploid hybrid clones of Populus tomentosa. The experiments aimed at unraveling genetic effect and clone × site interactions on chemical properties of wood and growth traits of corewood derived from triploid hybrid clones of P. tomentosa. Four 5-year-old clonal trials established in northern China were used to determine the clonal variations and clone × site interactions of chemical properties of wood and growth traits. Two hundred sixteen trees from nine clones were sampled in the four sites. Site had a highly significant (P < 0.001) effect on extractives and tree growth and a moderate effect on lignin and holocellulose. Clonal effects were also significant (P < 0.05) for all studied traits. Clone × site interactions were significant for all studied traits except for holocellulose. No significant estimated correlations between chemical properties of wood and growth traits were observed. However, a weak and negative estimated correlation between lignin and growth traits existed. This suggests that selection for growth traits might lead to a minor reduction in lignin in triploid breeding of P. tomentosa. Our results revealed that chemical properties of wood were under stronger genetic control than growth traits in triploid hybrid clones of P. tomentosa. Therefore, breeding programs might be able to improve these chemical properties of wood and growth traits in these hybrids.