| Popis: |
Tree breeders worldwide have highlighted the importance of wood quality within the juvenile core in determining final timber strength. The potential for improving timber strength by estimating genetic parameters of certain wood properties of Sitka spruce (Picea sitchensis) within the outer zone of the juvenile core was investigated. Fifteen trees were sampled from each of 33 families selected from a 20 year old open pollinated progeny trial. A number of wood properties critical to wood strength were measured; namely, density, grain angle, microfibril angle and branching characteristics. Clearwood stiffness and strength along with indirect measures of stiffness using acoustics and density using Pilodyn measurements were assessed. All wood properties were moderately heritable, wood density and acoustic velocity were the most heritable traits (h2 i 0.71 and 0.67 respectively). Genetic correlations showed that wood strength and stiffness were strongly correlated with wood density (0.86 and 1.04 respectively) and microfibril angle (-0.79 and -0.62 respectively). Acoustic velocity was strongly correlated with wood stiffness (0.81) and microfibril angle (- 0.83). The ability to select trees for wood stiffness with the use of acoustics along with the moderate inheritance of this trait should enable improvements in the wood quality of Sitka spruce. Despite the unfavourable correlation between growth rate and some key wood quality traits associated with timber strength, selection of certain families would enable modest gains to be made in both growth rate and wood quality. |
