What is the genetic origin of teak (Tectona grandis L.) introduced in Africa and in Indonesia?

The first introduction of Tectona grandis in Indonesia took place between the fourteenth and sixteenth centuries and in Africa in the nineteenth century. A total of 1.1 and 0.3 million ha, respectively were planted in the two areas. The extension of teak plantations often started from these first introductions. Unfortunately, the documentation concerning dates, planting stocks and the sources of origin of the teak imported into the different countries was very inaccurate. In this study, the use of 15 microsatellite molecular markers enabled us to compare 22 exotic teak provenances with 17 provenances of the natural range. Results of the analysis showed that the provenances from South India were not related to the provenances that were first introduced in either Africa or Indonesia. Nearly 95% of teak landraces in Benin, Cameroon, Cte d'Ivoire, Tanzania, Togo and Senegal came from North India, and 96% of Indonesian and Ghanaian teak appeared to be very closely linked to Central Laos. The genetic origin of introduced teak was confirmed by the main traits of interest of provenances observed in international trials. Thus, trees from North India had very bad stem forms compared to Laotian and Thai provenances, which generally had good stem forms but low vigour. This genetic knowledge is essential for programmes to develop varieties and to improve the quality of plantations, particularly in Africa.