Roles of European and Japanese larch in the genetic control of growth, architecture and wood quality traits in interspecific hybrids (<i>Larix � eurolepis</i> Henry)

Abstract

The respective roles of European and Japanese larch species in the genetic control of traits in interspecific hybrids are examined. Two incomplete factorial mating design experiments involving European larch clones of Sudetan origin as the female parent and Japanese larch clones as the male parent have been used for that purpose. Traits investigated include growth, architecture and wood quality parameters up to 16 years old. Results indicate that traits can be grouped into three categories according to the level of control by parental species: (i) height growth controlled nearly equally by both parents, (ii) BH diameter, stem volume and architecture traits under a strong Japanese larch control and (iii) wood quality parameters predominantly controlled by the European larch. Several traits showed moderate to high full-sib family heritabilities (over 0.8): total height, stem volume, branch angle and wood density, while others like heartwood proportion, taper, density of branching or stem straightness showed low values. Several traits appear to be under non-negligible non-additive genes effects: heartwood proportion, taper, stem straightness, BH girth and modulus of elasticity. Implications for further breeding are discussed.