Genetic Diveristy of a Multipurpose Tree Species in the
Caribbean Islands
P.LABBE, C.LEMAIRE
INRA CRAAG BP515, 97165 Pointe à Pitre
© Photo courtesy of INRA.
Tabebuia heterophylla is a pioneer species that has colonized the Carribean islands
from Trinidad to Cuba. It has a wide ecological range growing on wet and dry sites, on
volcanic and calcareous soils. Two ecotypes were recognised (3 and 5 leaflet) growing on
different soil types. This species is widely used for veneer, fuel, construction and
charcoal.
Tabebuia heterophylla has been over exploited and suffers severely of genetic erosion
throughout its natural distribution. Therefore a survey of genetic diversity was conducted
aiming at inventorying levels of diversity in the different islands and at identifying
major trends of variation, Samples from 11 islands were collected and diversity levels
were estimated at 19 RAPD loci.
There is a clear trend of variation of the level of diversity among the different
islands, Populations from southern latitudes show less diversity than those from central
and northern latitudes. Similarly allelic frequencies show also a latitudinal trend of
variation.
The geographic trends are most likely related to the geological history of the
Caribbean islands, as suggested by the similar trends of variation of genetic diversity
shown by animal species.
© Photo courtesy of INRA.
Measures are being taken to conserve genetic diversity by grafting trees that were
sampled for the genetic inventory; the grafts were installed on a clone bank and in seed
orchards.
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