Inheritance of wood properties and their radial variations in full-sib families of 36-year-old Japanese larch ( Larix kaempferi (Lamb.) Carr.)

Key message Larger differences of maximum load among families were found in mature wood compared to juvenile wood, suggesting the possibility of improving mature wood with higher resistance to rupture and maintaining characteristics of material in Larix kaempferi (Lamb.) Carr. by selecting specific mating parents. Context Because the wood from L. kaempferi trees is used for construction lumber, wood properties and bending properties should be focused on as targeted traits of tree breeding programs. Aims We clarified the radial variation of inheritance for wood properties and bending properties and classified the features of bending properties among families in L. kaempferi . Methods Annual ring width, latewood percentage, air-dry density, microfibril angle, modulus of elasticity, modulus of rupture, and bending work at five radial positions were investigated for 15 full-sib families of 36-year-old L. kaempferi grown in two progeny test sites in Japan. Results Higher heritability at almost all radial positions was found in air-dry density. Phenotypic and genetic correlations between air-dry density and bending properties showed relatively higher values at almost all radial positions. Load-deflection curves in 15 families could be divided into three groups in juvenile and mature wood. Variation among groups for load-deflection curves in mature wood was relatively larger than that in juvenile wood. Conclusion Air-dry density can be used as a criterion to select trees with superior bending properties. Mature wood in L. kaempferi could be effectively improved by selecting individuals.