| AVAILABILITY
OF PLANTING MATERIALS
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.
|
