Worldwide translocation of teak-origin of landraces and present genetic base

Teak (Tectona grandis Linn. f.) is one of the major plantation timbers of the world. The species is native to India, Myanmar, Thailand and Laos in South East Asia but was translocated to several countries in Africa and Central and South America during the past century. Today, large areas of plantations are grown outside the species native range. It is speculated that genetic bottlenecks and founder effects combined with new selection pressures under new growing conditions have led to the formation of distinct landraces; this hypothesis is supported by results from international provenance tests. In the present study, we apply genetic markers to identify the likely origin of teak grown outside its native range and examine if the landraces show signs of reduced genetic diversity. We find large variation in the level of diversity among landraces, although not larger than that observed among native populations. We conclude that variation in the studied teak landraces probably reflects their areas of genetic origin rather than severe founder effects created during their introduction. The genetic data suggests that the studied land-races originated from either the semi-moist east coast of India, southern Myanmar or western Thailand. These results indicate that translocation of teak has mainly come from a certain part of the native distribution and that this did not include the widespread natural teak areas of southern, dry interior or western India or northern Myanmar.