Inheritance of wood color, decay resistance, and polyphenol content of heartwood in full-sib families of Japanese larch (Larix kaempferi (Lamb.) Carr.)

Japanese larch (Larix kaempferi) is an important plantation species in Japan as well as in Europe. The inheritance of wood color (L*, a* and b*), mass loss by a white-rot fungus (Trametes versicolor) and a brown-rot fungus (Fomitopsis palustris), and polyphenol content (as the taxifolin equivalent) in heartwood were examined for 75 trees in 15 full-sib families of L. kaempferi. The mean values of all trees were 74.5 in L*, 8.4 in a*, 23.0 in b*, 18.3 and 26.0% in mass loss by T. versicolor and F. palustris, and 0.045 mu mol/mg in polyphenol content. The narrow-sense heritability (h(2)) showed higher values in heartwood color (h(2) = 0.70-0.87), but mass loss and polyphenol content showed relatively lower values (h(2) = 0.00-0.33). Significant negative correlations were found between polyphenol content and mass loss by white-rot and brown-rot fungi. In addition, the polyphenol content of heartwood was significantly correlated with the color of heartwood. Similar results were obtained in genetic correlations. Thus, it is concluded that parents with lower L* and higher a* and b* in heartwood could produce progenies with higher polyphenol content in heartwood, thereby leading to higher decay resistance.