Genetic variation and relationships to growth traits for microfibril angle, wood density and modulus of elasticity in a Picea abies clonal trial in southern Sweden

Abstract

Genetic variation in wood density, microfibril angle (MFA), wood stiffness (MOE), height, diameter and volume was investigated in a 26-year-old Norway spruce [(Picea abies (L.) Karst.] clonal trial in southern Sweden. Wood quality measurements were performed on 10 mm increment cores using SilviScan. For MFA, mean values of annual rings showed the highest value (30°) at ring 2 counting from the pith, followed by a steep decrease and a gradual stabilization around ring 12 at approximately 14°. MOE showed a monotonic increase from 5 GPa to 14 GPa when moving from pith to bark. High broad-sense heritability values were found for wood density (0.48), MFA (0.41) and MOE (0.50). All growth traits displayed heritability values of similar magnitudes as reported in earlier studies. The generally high age–age correlations between different sections of the wood cores suggested that early selection for wood quality traits would be successful. Owing to unfavorable genetic correlations between volume and MOE, the correlated response indicated that selection for volume only at age 10 would result in a 0.27% decrease in weighted MOE at age 26 for every 1% increase in volume.

Keywords:

• Juvenile wood
• solid wood products
• X-ray diffraction

Acknowledgements

This study was supported by funds from the Swedish Tree Breeding Association, the Nordic Forest Research Co-operation committee (SNS), the Swedish Research Council Formas, and the Gunnar and Lilian Nicholson Fellowship at NC State University. Also, thanks to Skogforsk, STFI-Packforsk, the North Carolina State University Department of Forestry and Environmental Resources, the NCSU Cooperative Tree Improvement Program, and the Swedish University of Agricultural Sciences (SLU), School for Forest Engineers. In addition, the following persons made contributions to the study: Gudmund Ahlberg (Skogforsk), Robert Evans (CSIRO Forestry and Forest Products), Åke Hansson (STFI-Packforsk), Bo Karlsson (Skogforsk), Lars Olsson (STFI-Packforsk), Gunnar Jansson (Skogforsk) and Arne Steffenrem (Norwegian Forest and Landscape Institute).