Ebony (Diospyros celebica Bakh.) is an endemic plant on Celebes (Sulawesi) island. Extractive compounds within ebony wood cause it to have durability, strength, and beautiful patterns. In this study, we used near-infrared (NIR) spectroscopy to discriminate between ebony wood samples, based on their origins at different growth sites on Celebes island, and to develop quantitative models to predict the extractive content of ebony wood. A total of 45 wood meal samples from 11 sites located in West, Central, and South Celebes were collected in this study. NIR spectral data were acquired from hot water and ethanol–benzene soluble extracts from ebony wood in this study. The extractive content of the ebony was 10.408% and 10.774% based on hot water solubility and treatment with ethanol–benzene solvent, respectively. Multivariate analysis based on principal component analysis–discriminant analysis revealed that ebony wood from West Celebes differed from most of the wood from South Celebes; however, it was only slightly different from ebony wood from Central Celebes based on NIR spectra data. These findings were in line with the extractive contents obtained. Partial least square regression models based on wood meal spectra could potentially be used to estimate the hot water and ethanol–benzene extractive contents from ebony wood.

Ritonga FN, Dwiyanti FG, Kusmana C, Siregar UJ, Siregar IZ. 2018. Population genetics and ecology of Sumatran camphor (Dryobalanops aromatica) in natural and community-owned forests in Indonesia. Biodiversitas 19: 2175-2182. Dryobalanops aromatica Gaertn. f. (Sumatran camphor) is a valuable tree species that produces borneol (camphor) and good-quality timber. However, the population of this species has declined due to illegal logging and conversion of forests into plantations and has been classified as Critically Endangered by the International Union for Conservation of Nature. This study aimed to examine the genetic variation and spatial distribution of this species in a community-owned forest (Barus) and two natural forests (Singkohor and Danau Paris) in Indonesia using the Random Amplified Polymorphic DNA marker. The results of this study showed that D. aromatica had moderate levels of genetic variation (expected heterozygosity [He] = 0.1760 [Barus population] to 0.2134 [Singkohor population]) and genetic differentiation (Nei’s Gst = 0.1257). The genetic distance was the smallest between the Singkohor and Danau Paris populations (Nei’s distance = 0.0363) and greatest between the Singkohor and Barus populations (Nei’s distance = 0.0534). The spatial distribution of D. aromatica was grouped in both Barus and Danau Paris based on Morisita’s index of diversity (ip = 0.06 and 0.043, respectively). These findings indicated that genetic conservation might be performed in situ in combination with enrichment planting using locally propagated sources.

Kapur (Dryobalanops aromatica) is an important dipterocarp species currently classified as vulnerable by the IUCN Red List Threatened Species. Science-based conservation and restoration efforts are needed, which can be supported by new genomic data generated from new technologies, including MinION Oxford Nanopore Technology (ONT). ONT allows affordable long-read DNA sequencing, but this technology is still rarely applied to native Indonesian forest trees. Therefore, this study aimed to generate whole genome datasets through ONT and use part of these data to construct the draft of the chloroplast genome and analyze the universal DNA barcode-based genetic relationships for D. aromatica. The method included DNA isolation, library preparation, sequencing, bioinformatics analysis, and phylogenetic tree construction. Results showed that the DNA sequencing of D. aromatica resulted in 1.55 Gb of long-read DNA sequences from which a partial chloroplast genome (148,856 bp) was successfully constructed. The genetic relationship was analyzed using two selected DNA barcodes (rbcL and matK), and its combination showed that species of the genus Dryobalanops had a close relationship as indicated by adjacent branches between species. The phylogenetic tree of matK and the combination of the matK and rbcL genes showed that D. aromatica was closely related to Dryobalanops rappa, whereas the rbcL gene showed group separation between D. aromatica and D. rappa. Therefore, a combination of the matK and rbcL genes is recommended for future use in the phylogenetic or phylogenomic analysis of D. aromatica.

Genetic variation and structure of Ubame oak (Quercus phillyraeoides A. Gray), a shrub tree on the Pacific coast of Japan, were examined to elucidate historical population dynamics using five chloroplast DNA (cpDNA) marker regions and 11 nuclear microsatellite loci. Three cpDNA haplotypes (A, B and C) were identified in a screen of 41 populations across the entire distribution range in Japan. Haplotype A was the most prevalent and was found in the entire range. Haplotype B was locally restricted to the Kii Peninsula, while haplotype C was restricted to the southwestern part of Japan. These haplotypes corresponded with the nuclear genetic constitution revealed by microsatellite markers. Two genetically differentiated major groups were identified by STRUCTURE analysis applied to 536 individuals from 28 populations, and they mostly corresponded with the two major cpDNA haplotypes, A and C. These populations were further divided into three geographically identified groups: group 1 in the area including Kanto and Tokai regions, the Kii Peninsula and the Muroto-misaki Cape on the Pacific coast; group 2 in the Bungo-suido Channel area; and group 3 in southern Kyushu and Okinawa. Populations in the Seto Inland Sea were divided into two groups: one was included in group 1 and appears to have originated from last glacial maximum (LGM) refugia located in the Kii Peninsula, while the other was included in group 2 and appears to have originated from LGM refugia located in southern Kyushu. These groups can be considered as conservation units for the preservation of unique seashore ecosystems, or as a seed source to foster coastal protection forests and next-generation production forests. Considerable care should be taken to protect isolated populations that may be specialized to unique local environments, such as those on the islands of Koshikijima and Izenajima.