Possibility of tree breeding for wood quality in keyaki（Zelkova serrata）

Abstract

To evaluate the possibility of tree breeding for wood quality in keyaki（Zelkova serrata（Thunb.）Makino）, wood quality of logs was investigated for 11 strains of 20-year-old trees planted in Chiba, Japan. Mean values of moisture content, basic density, modulus of elasticity（MOE）and modulus of rupture（MOR）were 56.3%, 0.61 g/cm³, 6.43GPa, and 73.5MPa, respectively. Relatively higher F-values in analysis of variance test were found in all characteristics, except for moisture content, suggesting that wood quality of keyaki could be improved by selection of superior trees through tree breeding programs. No significant correlations were observed between stem diameter and wood quality, except for MOR. It is considered that, in keyaki, the trees with higher growth rate do not always have lower wood quality. Furthermore, stress-wave velocity of stem was positively correlated with MOE and MOR of logs, indicating that stress-wave velocity is one of the useful indicators to select the trees with higherstrength properties of wood in keyaki.