Genetic diversity in teak trees strongly related to temperature — Indian populations show high adaptability to climate

A research group consisting of Graduate Student Yunosuke Onuma from the University of Tsukuba Degree Program in Agricultural Sciences, Professor Emeritus Yoshihiko Tsumura from the University of Tsukuba Institute of Life and Environmental Sciences, and Senior Researcher Naoki Tani from the Japan International Research Center for Agricultural Sciences (JIRCAS), in collaboration with Gadjah Mada University in Indonesia, announced on July 4 that they have revealed that the genetic diversity of teak (Tectona grandis), an important tree species used in furniture, is strongly related to temperature. The study investigated genetic diversity in areas of natural distribution and areas of planted trees in Indonesia. It was revealed that populations in southern India have high adaptability to temperature and precipitation variations under climate change. This is expected to contribute to adaptation measures in the forestry sector. The results were published in Forest Science and Technology on June 23.

Trees are long-lived and require several years to decades for growth, and because they are sessile, they are thought to be strongly affected by climate change. Tropical forests in particular are vulnerable to climate change, making it necessary to quickly clarify the genetic adaptability of each tree species and regional population, and to develop planting plans as countermeasures.

Teak (Lamiaceae family, genus Tectona) is one of the world's most valuable tropical hardwood species used for furniture and other purposes, with a natural distribution range from India to Indochina in tropical regions. It is currently planted in approximately 65 countries worldwide.

Previous studies using genetic information reported that populations naturally distributed in India show different patterns of genetic diversity compared with populations outside India. However, it was not understood how this difference relates to environmental adaptation.

Therefore, this research group collected seeds from natural distribution areas and collected samples from international provenance trial forests planted on Java Island, Indonesia, and from plantations on Java Island, and examined SNPs (single nucleotide polymorphisms) on the genome.

They found that populations distributed in India had large genetic variation, and among them, the genetic composition of populations distributed in Malabar in southern India differed most significantly from other Indian populations. Next, when they examined the relationship between the distribution pattern of genomic polymorphisms between individuals and the environment, they found regions showing particularly strong correlations with mean temperature during the rainy season.

Furthermore, when they evaluated adaptability to temperature and precipitation, they found that populations in southern India have high adaptability.

In the future, clarifying the comprehensive environmental adaptability of teak and reflecting this in planting plans at an early stage is expected to enhance resilience to climate change.

Tsumura commented: "Global warming has many impacts on forestry as well. Forestry, in particular, requires a long period from planting to harvesting and needs a selection of materials suitable for future warming. We believe the results of this research will be useful for the sustainable forestry of teak after global warming and that the use of this method can contribute not only to tropical forestry but also to forestry in temperate regions."

Journal Information
Publication: Forest Science and Technology
Title: Genomic adaptation in teak (Tectona grandis) to local climatic conditions and implication for resilient planting strategies on Java Island
DOI: 10.1080/21580103.2025.2519469