Teak plants can be raised using either seeds or vegetative tissues (stumps, branch cuttings etc.). Plants raised from seeds collected at random tend to show fairly wide variability in growth, while vegetative propagation using cuttings and tissue culture ensures production of uniform planting materials of desired qualities. However, seeds are very important to maintain a broad genetic base. To obtain fairly uniform planting materials from seeds, seedling or colonel seed orchards of good-quality trees have to be raised for seed collection.
The large variation in growth conditions within the natural range of teak suggests that there is a likelihood of substantial genetic variability among provenance's. Furthermore, the long-term cultivation of teak in regions outside its endemic area (e.g. in Java, Indonesia) suggests the possible existence of land races that are specifically adapted to the regions to in which teak has been introduced.
To examine these questions, an international series of provenance trials was established (Keiding, Wellendorf and Lauridsen, 1986; Kjaer, Lauridsen and Wellendorf, 1995; Kjaer and Foster, 1996). These trials showed that, in general, local seed sources should be preferred when teak is established within the area of its natural distribution (White, 1991). Although local sources did not always give the fastest growth rates, they consistently gave good performance relative to seed lots introduced from elsewhere.
In contrast, for regions outside the natural range of teak, local seed lots were sometimes very poor for some characters of commercial significance and were thus unsuitable for use in developing commercial-scale plantations. Of particular interest, however, was the broad adaptation of provenance's from southern India and Indonesia, which exhibited good survival, growth rates and form.
Plant stocks currently being used for the Malaysian plantation programs principally originate from local unidentified sources or from Thailand. There is no accreditation to ensure that the material comes from a reliable source of good-quality germplasm or, indeed, from the source named by the supplier. This presents a risk for plantation managers. FRIM is currently working with some reliable commercial nurseries and plant propagators to produce large enough quantities of high-quality plants to meet Malaysia's needs.
Most plants stocks in the Costa Rica and Panama area comes from Myanmar. The stock has exhibited very good properties for plantations in Central America.