Intraspecific adaptation inAbies sachalinensiswas examined using models based on long‐term monitoring data gathered during a reciprocal transplant experiment with eight seed source populations and six transplantation sites along an altitudinal gradient. The consequence of local adaptation was evaluated by testing the home‐site advantage for upslope and downslope transplants at five ages. The populations’ fitness‐linked trait was set as their productivity (tree height × survival rate) at each age. The effects of global warming were evaluated on the basis of the 36‐year performance of downslope transplants. Evidence was found for adaptive genetic variation affecting both height and survival from an early age. Increasing the distance between seed source and planting site significantly reduced productivity for both upslope and downslope transplantation, demonstrating the existence of a significant home‐site advantage. The decrease in productivity was most distinct for upslope transplantations, indicating strong local adaptation to high altitudes. Global warming is predicted to increase the productivity of high‐altitude populations. However, owing to their existing local adaptation, all tested populations exhibited lower productivity under warming than demes that were optimal for the new climate. These negative predictions should be considered when planning the management of locally adapted plant species such asA. sachalinensis.

Research Highlights: We detected the longitudinal gradients of genetic diversity parameters, such as the number of alleles, effective number of alleles, heterozygosity, and inbreeding coefficient, and found that these might be attributable to climatic conditions, such as temperature and snow depth. Background and Objectives: Genetic diversity among local populations of a plant species at its distributional margin has long been of interest in ecological genetics. Populations at the distribution center grow well in favorable conditions, but those at the range margins are exposed to unfavorable environments, and the environmental conditions at establishment sites might reflect the genetic diversity of local populations. This is known as the central-marginal hypothesis in which marginal populations show lower genetic variation and higher differentiation than in central populations. In addition, genetic variation in a local population is influenced by phylogenetic constraints and the population history of selection under environmental constraints. In this study, we investigated this hypothesis in relation to Abies sachalinensis, a major conifer species in Hokkaido. Materials and Methods: A total of 1189 trees from 25 natural populations were analyzed using 19 EST-SSR loci. Results: The eastern populations, namely, those in the species distribution center, showed greater genetic diversity than did the western peripheral populations. Another important finding is that the southwestern marginal populations were genetically differentiated from the other populations. Conclusions: These differences might be due to genetic drift in the small and isolated populations at the range margin. Therefore, our results indicated that the central-marginal hypothesis held true for the southernmost A. sachalinensis populations in Hokkaido.

We grafted scions of Dahurian larch (Larix gmelinii var. japonica) onto Japanese larch (L. kaempferi) and F1 hybrid larch (L. gmeli­nii var. japonica × L. kaempferi) rootstocks and examined root­stock-scion compatibility by assessing the survival rate (SR) in two independent experiments. Scion overgrowth on the root­stock was not observed. SR was not significantly different among rootstocks due to large interquartile ranges (IQR) among clones within a rootstock type. Results suggested that the SR was more dependent on the clonal characteristics of the scion than on the growth vigor of the rootstock. Shoot elonga­tion of grafts on F1 hybrid rootstock was superior to that of grafts on Japanese larch rootstock. Selection of an appropriate combination of scion and rootstock may improve the SR of grafted Dahurian larch and shorten the cultivation period.

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch.

Todo-matsu (Abies sachalinensis) is one of the most important forestry species in Hokkaido, Japan and is distributed from near sea level to the alpine zone. Due to its wide spatial distribution, the species adapts to its environment, displaying phenotypes of ecological relevance. In order to identify candidate genes under natural selection, we collected the transcriptome from the female and male flower, leaf and inner bark. De novo assembly with 34.7 Gb of sequencing reads produced 158,542 transcripts from 69,618 loci, whose estimated coverage reached 95.6% of conserved eukaryotic genes. Homology searches against publicly available databases identified 134,190 (84.6%) transcripts with at least one hit. In total, 28,944 simple sequence repeats (SSRs) and 80,758 single nucleotide variants (SNVs) were detected from 23,570 (14.9%) and 25,366 (16.0%) transcripts, which were valuable for use in genetic analysis of the species. All the annotations were included in a relational database, TodoFirGene, which provides an interface for various queries and homology search, and can be accessed at http://plantomics.mind.meiji.ac.jp/todomatsu/. This database hosts not only the A. sachalinensis transcriptome but also links to the proteomes of 13 other species, allowing a comparative genomic study of plant species.

Research highlights: Using 10-year tree height data obtained after planting from the range-wide provenance trials of Abies sachalinensis, we constructed multivariate random forests (MRF), a machine learning algorithm, with climatic variables. The constructed MRF enabled prediction of the optimum seed source to achieve good performance in terms of height growth at every planting site on a fine scale. Background and objectives: Because forest tree species are adapted to the local environment, local seeds are empirically considered as the best sources for planting. However, in some cases, local seed sources show lower performance in height growth than that showed by non-local seed sources. Tree improvement programs aim to identify seed sources for obtaining high-quality timber products by performing provenance trials. Materials and methods: Range-wide provenance trials for one of the most important silvicultural species, Abies sachalinensis, were established in 1980 at nine transplanting experimental sites. We constructed an MRF to estimate the responses of tree height at 10 years after planting at eight climatic variables at 1 km × 1 km resolution. The model was applied for prediction of tree height throughout Hokkaido Island. Results: Our model showed that four environmental variables were major factors affecting height growth—winter solar radiation, warmth index, maximum snow depth, and spring solar radiation. A tree height prediction map revealed that local seeds showed the best performance except in the southernmost region and several parts of northern regions. Moreover, the map of optimum seed provenance suggested that deployment of distant seed sources can outperform local sources in the southernmost and northern regions. Conclusions: We predicted that local seeds showed optimum growth, whereas non-local seeds had the potential to outperform local seeds in some regions. Several deployment options were proposed to improve tree growth.