Genetic gains in wood property can be achieved by indirect selection and nondestructive measurements in full-sib families of Japanese cedar (Cryptomeria japonica. D. Don) plus tree clones

Key message We assessed the narrow-sense heredity and genetic gains of multiple traits obtained using the indirect selection method for progeny of Cryptomeria japonica D. Don by artificial crossing. Using stress wave velocity and Pilodyn penetration depth as indicative parameters, wood properties could be improved in future generations of C. japonica plus trees and forest breeding programs will become more efficient. Context To advance generations of C. japonica D. Don breeding populations, the narrow-sense heredity and genetic gain of traits of progenies are required to assess the practical genetic performance of parental trees and improve traits. Aims We assessed the genetic gains in both growth characteristics and wood properties by indirect selection using full-sib progenies of C. japonica plus trees produced through artificial crosses. Methods In 18-year-old progenies of 549 trees, we assessed growth characteristics, dynamic modulus of elasticity, basic density, stress wave velocity, and Pilodyn penetration depth. Genetic parameters were calculated using a mixed model and the breedR package. Results The genetic correlation between growth characteristics and wood properties was low. The efficiencies of indirect selection for dynamic modulus of elasticity by stress wave velocity and for basic densities by Pilodyn penetration depth were higher than those for growth characteristics by stress wave velocity and Pilodyn penetration depth, respectively. Strong correlations were found between the parental clonal values and breeding values of parental trees predicted from progeny using stress wave velocity and Pilodyn penetration depth. Conclusion Using stress wave velocity and Pilodyn penetration depth as indicative parameters, future generations of C. japonica plus trees could produce superior wood properties. Growth characteristics and wood properties are independent; thus, both traits could be genetically improved compatibly.