Breeding a hybrid larch in Hokkaido, northern Japan

Japanese larch (Larix kaempferi) is an important afforestation species in the boreal temperate zone. However, this species is sensitive to vole (Myodes rufocanus bedfordiae) gnawing and shoot blight disease by Botryosphaeria laricina. We developed the hybrid larch (L. gmelinii var. japonica × L. kaempferi) to overcome these problems. In addition to improving the resistance to vole gnawing and shoot blight disease, this hybrid showed high wood density and carbon accumulation ability, calculated with DBH, tree height, wood density, and tree number/ha. Wood density is inherited equally from the female and male parents, and growth traits are mainly inherited from the male parent. The hybrid larch exhibited a high Young’s modulus and its expected use was for medium and high-rise buildings. Hybridization rates were higher (84.2 – 94.1%) in a single maternal clone seed orchard compared to a multi-clone female and male seed orchard. We propagated nursery stocks of high carbon accumulating females (named “Clean-larch”) by rooted cutting with hybridized seedlings produced in a single maternal clone seed orchard. The hybrid larch is susceptible to Armillaria root rot. A research task left for the future is to find the optimum method for selecting the planting area for hybrid larch and Japanese larch

Color strategies of camellias recruiting different pollinators

Mori, Shinnosuke, Hasegawa, Yoichi, Moriguchi, Yoshinari (2023): Color strategies of camellias recruiting different pollinators. Phytochemistry (113559) 207: 1-9, DOI: 10.1016/j.phytochem.2022.113559, URL: http://dx.doi.org/10.1016/j.phytochem.2022.11355

Factors Affecting the Number of Pollen Grains per Male Strobilus in Japanese Cedar (Cryptomeria japonica)

Japanese cedar (Cryptomeria japonica) is the most important timber species in Japan; however, its pollen is the primary cause of pollinosis in Japan. The total number of pollen grains produced by a single tree is determined by the number of male strobili (male flowers) and the number of pollen grains per male strobilus. While the number of male strobili is a visible and well-investigated trait, little is known about the number of pollen grains per male strobilus. We hypothesized that genetic and environmental factors affect the pollen number per male strobilus and explored the factors that affect pollen production and genetic variation among clones. We counted pollen numbers of 523 male strobili from 26 clones using a cell counter method that we recently developed. Piecewise Structural Equation Modeling (pSEM) revealed that the pollen number is mostly affected by genetic variation, male strobilus weight, and pollen size. Although we collected samples from locations with different environmental conditions, statistical modeling succeeded in predicting pollen numbers for different clones sampled from branches facing different directions. Comparison of predicted pollen numbers revealed that they varied >3-fold among the 26 clones. The determination of the factors affecting pollen number and a precise evaluation of genetic variation will contribute to breeding strategies to counter pollinosis. Furthermore, the combination of our efficient counting method and statistical modeling will provide a powerful tool not only for Japanese cedar but also for other plant species

An efficient method for developing SNP markers based on EST data combined with high resolution melting (HRM) analysis

Abstract Background In order to identify single nucleotide polymorphisms (SNPs) efficiently from a species with a large genome, SNPs were identified from an expressed sequence tag (EST) database combined with High Resolution Melting (HRM) analysis. Findings A total of 574 sequence tagged sites (STSs) were generated from Cryptomeria japonica and HRM analysis was used to screen for polymorphisms in these STS markers. STSs were designed in two ways: 1) putative SNP sites were identified by comparing ESTs from specific contigs, then 226 primer pairs designed for the purpose to amplify these SNPs; 2) 348 primer pairs were randomly designed using reads from the 3' end of cDNA. HRM analysis revealed that 325 markers among eight individuals were polymorphic, and that STSs, including putative SNP sites, exhibited higher levels of polymorphism. Conclusion Our results indicate that the combination of SNP screening from an EST database combined with HRM analysis is a highly efficient way to develop SNP markers for expressed genes. This method will contribute to both genetic mapping and the identification of SNPs in non-model organisms.</p

Data from: Genome scanning for detecting adaptive genes along environmental gradients in the Japanese conifer, Cryptomeria japonica

Local adaptation is important in evolutionary processes and speciation. We used multiple tests to identify several candidate genes that may be involved in local adaptation from 1026 loci in 14 natural populations of Cryptomeria japonica, the most economically important forestry tree in Japan. We also studied the relationships between genotypes and environmental variables to obtain information on the selective pressures acting on individual populations. Outlier loci were mapped onto a linkage map, and the positions of loci associated with specific environmental variables are considered. The outlier loci were not randomly distributed on the linkage map; linkage group 11 was identified as a genomic island of divergence. Three loci in this region were also associated with environmental variables such as mean annual temperature, daily maximum temperature, maximum snow depth, and so on. Outlier loci identified with high significance levels will be essential for conservation purposes and for future work on molecular breeding