Genetic effects on heartwood color variation in Cryptomeria japonica

Abstract

To obtain fundamental and useful information regarding heartwood color traits in Japanese cedar, the validity of using L* index for expressing heartwood color and genetic and environmental influences on heartwood color were analyzed using 118 clones with 303 individuals aged approximately 30 years. As for three clones with typical reddish and blackish heartwood, relationships between heartwood color and moisture/potassium content, which were pointed out as ones of the causative agents of blackish heartwood, and the color change after approximately 20 years of conservation were investigated. Based on the continuity, width range, and standard deviation of each index of L*a*b* data, L* was found out to be an appropriate index to express heartwood color in this species. L* values significantly differed between clones. A moderately high repeatability of clones was detected in L* value. Spatial autocorrelation analysis also showed a stronger effect genetically than environmentally. Moisture and potassium contents significantly differed between two groups of reddish and blackish heartwood. Therefore, the absorption and accumulation of water and potassium into trunk may be genetically regulated. As for the L* value of heartwood color after approximately 20 years of conservation, the difference between two groups was still significant, but the lightness in blackish heartwood increased such that the difference was greatly reduced.

Genotype-by-environment interaction and genetic dissection of heartwood color in Cryptomeria japonica based on multiple common gardens and quantitative trait loci mapping

“…The large contribution of genetic effects in the heartwood color of C . japonica was also reported in a previous study conducted in a single forest stand [ 28 ]. These findings indicated that heartwood colors in this species have high potential to be improved through breeding in various environmental conditions, which is particularly important for long-lived forest trees that experience substantial environmental changes such as ongoing climate change.…”

“…japonica . Furthermore, these suggested that heartwood color is not only important in terms of esthetic value but also a valuable indicator that represent wood moisture which could affect drying processes of the wood [ 28 ].…”

“…For example, a previous study conducted in a single forest stand reported that the brightness of heartwood color ( L *) largely differs between different clones of C . japonica , and moisture and potassium content are correlated with heartwood color [ 28 ]. In addition, darker heartwood color is less preferred for the usage of non-laminated wood such as in traditional construction [ 28 ].…”

“…japonica , and moisture and potassium content are correlated with heartwood color [ 28 ]. In addition, darker heartwood color is less preferred for the usage of non-laminated wood such as in traditional construction [ 28 ]. However, the genetic basis of genotype-by-environment interaction and the genomic regions controlling heartwood color in C .…”

A Review of the Factors Influencing Variations in the Heartwood Proportion for Solid Wood

“…Similar results were also obtained in Eucalyptus cladocalyx F.Muell (Bush 2011) and P. sylvestris (Ericsson and Fries 1999), where the proportion of heartwood was affected by genetics. Miyamoto et al (2016) reported that its color was mainly controlled by genetics rather than the environment based on the spatial autocorrelation analysis. Previous studies also revealed that the color was influenced genetically, and there were clear differences between the clones (Kurinobu et al 1992, Nakada 2007.…”