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ABSTRACTIn order to provide basic information on genetic improvement potential in Cryptomeria japonica(sugi), we estimated genetic parameters, direct and indirect genetic gains and optimum selection ages for growth traits based on the data obtained from 429 progeny test sites located throughout Japan. Medians of narrow-sense heritabilites for height and diameter at breast height (DBH) were ranged in 0.289–0.445 and 0.235–0.276, respectively. The heritability of height significantly increased after the age of 15 years. On the other hand, there were no significant differences among ages in the heritability of DBH. Medians of the age-age genetic correlations were similar when the age differences of the pairs were the same, and tended to decrease as the age differences became larger for both height and DBH. The maximum efficiencies for gain per year when the target age is assumed to be 30 years were obtained at an age of 5 years in height and of 10 years in DBH, respectively. As the values at an age of 5 years in height varied greatly depending on test site, there would likely be selection errors. Thus, the early selection at 1/3 the target age is efficient in sugi.

Rapid and cost-effective methods of evaluating the properties of wood are required for forest-tree breeding programs. In this work, we first attempted to develop a calibration model for predicting the stiffness of wood using near-infrared (NIR) spectroscopy. Wood samples were collected from three stands of sugi (Cryptomeria japonica) plus-tree clones aged from 34 to 36 years old. Two to three sample trees were harvested from each clone, yielding a total of 129 sample trees. Partial least-squares analysis was performed to predict the dynamic modulus of elasticity (Efr). A reasonable calibration model that allowed Efrto be predicted with a correlation coefficient of 0.69 and a root mean square error of prediction of 0.82 GPa was obtained. Second, in a novel approach, we tried to select the NIR spectral bands that were the most strongly related to wood stiffness, and we examined the degree to which these bands were genetically controlled. The heritability estimates (h2) for the NIR absorbance values at 7,320 and 6,281 cm−1, which were found to be the most important bands for predicting Efr, were 0.48 and 0.57, respectively. Although the genetic control of the NIR spectral bands was weaker than the genetic control associated with the actual measurement of Efr(h2= 0.74), the results imply that the NIR spectral bands are under moderate genetic control. Assuming that the NIR spectral bands are the dissected components of the target trait (Efr), the results should provide useful information when attempting to perform genomics-based breeding.

AbstractRapid and cost-effective methods of evaluating the properties of wood are required for forest-tree breeding programs. In this work, we first attempted to develop a calibration model for predicting the stiffness of wood using near-infrared (NIR) spectroscopy. Wood samples were collected from three stands of sugi (Cryptomeria japonica) plus-tree clones aged from 34 to 36 years old. Two to three sample trees were harvested from each clone, yielding a total of 129 sample trees. Partial least-squares analysis was performed to predict the dynamic modulus of elasticity (Efr). A reasonable calibration model that allowed Efrto be predicted with a correlation coefficient of 0.69 and a root mean square error of prediction of 0.82 GPa was obtained. Second, in a novel approach, we tried to select the NIR spectral bands that were the most strongly related to wood stiffness, and we examined the degree to which these bands were genetically controlled. The heritability estimates (h2) for the NIR absorbance values at 7,320 and 6,281 cm−1, which were found to be the most important bands for predicting Efr, were 0.48 and 0.57, respectively. Although the genetic control of the NIR spectral bands was weaker than the genetic control associated with the actual measurement of Efr(h2= 0.74), the results imply that the NIR spectral bands are under moderate genetic control. Assuming that the NIR spectral bands are the dissected components of the target trait (Efr), the results should provide useful information when attempting to perform genomics-based breeding.

Genetic diversity is important in tree improvement programs. To evaluate levels of genetic diversity of first generation Acacia mangium seedling seed orchard in Wonogiri, Central Java, Indonesia, three populations from each region of Papua New Guinea (PNG) and Queensland, Australia (QLD) were selected and analyzed using 25 microsatellite markers. Statistical analysis showed that PNG populations have higher number of detected alleles and level of genetic diversity than QLD populations. This study provides a basic information about the genetic background of the populations used in the development of an A. mangium seed orchard in Indonesia.

DNA sequences of the chloroplast spacer region between the trnP and trnW genes (234 bps) were determined for two Japanese fir species, Abies firmaSieb. et Zucc. and A. homolepisSieb. et Zucc., using four individuals from each species. No intraspecific variation was found in either species, but interspecific sequence polymorphism was detected between the two species. The interspecific variation was three nucleotide changes, from the 148th to 150th nucleotide position. These three nucleotides were TAC in A. firmaand GTA in A. homolepis, which were inverted. In order to identify the cpDNA haplotypes between the two species, this inversion polymorphism was utilized to develop a new marker. Species-specific primers were designed so that the 3′ ends of the primers would anneal to the mutation site, in order for the two haplotypes to be easily identified by a polymerase chain reaction (PCR).

DNA sequences of the chloroplast spacer region between thetrnP andtrnW genes (234 bps) were determined for two Japanese fir species,Abies firmaSieb. et Zucc. andA. homolepisSieb. et Zucc., using four individuals from each species. No intraspecific variation was found in either species, but interspecific sequence polymorphism was detected between the two species. The interspecific variation was three nucleotide changes, from the 148th to 150th nucleotide position. These three nucleotides were TAC inA. firmaand GTA inA. homolepis, which were inverted. In order to identify the cpDNA haplotypes between the two species, this inversion polymorphism was utilized to develop a new marker. Species-specific primers were designed so that the 3′ ends of the primers would anneal to the mutation site, in order for the two haplotypes to be easily identified by a polymerase chain reaction (PCR).