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The Site
The Caroni River forms the northern boundary of the genebank, cocoa fields
of the La Reunion estate border the western and eastern sides,
with abandoned sugar-cane fields to the south. The site is characterised
by fine sandy-clay soil belonging to the Cunupia series which
has restricted internal drainage. The bed system and intricate
drainage system of earlier cocoa plantings were retained in establishing
the Genebank, since this avoided disturbing the delicate the top
soil. It also facilitates efficient removal of excess precipitation
in the wet season and provides the opportunity for irrigation
in the dry season.
Layout
The ICG,T at present consists of five blocks of accessions located in Fields
4A, 5A, 5B, 6A and 6B (a total of 20 ha). Four of these blocks
are subdivided into plots each holding sixteen plants, except
where the bed layout dictates otherwise. The spacing between
plants is 1.83m x 1.83m. After planting, temporary shade was
provided by non-commercial bananas, and permanent shade is given
by Erythrina sp. Field 4A (the fifth block) represents an intensive
system of germplasm conservation where introductions into Trinidad
are established on commercial rootstock prior to re-propagation
by rooted cuttings.
Each cacao accession in the ICG,T is represented by up to 16 closely planted
trees. This system quickly produces a closed canopy that, once
established, withstands periods of low input with minimum risk
to the genetic material. This design works well for accessions
which are easy to establish from cuttings, but for those that
are difficult to establish, gaps in the canopy exacerbates weed
control problems.
The Germplasm
Accessions in the ICG,T represent the major groups
of cacao (Forastero, Criollo, Trinitario and Refractario) as
well as related species of Theobroma. About 40% of the accessions
are in the Forastero group, 40% in the Refractario group, 10%
in the Trinitario group and the remainder either Criollo, hybrids
or unclassified. There is a constant introduction of new material
to the ICG,T, either
from collection expeditions to obtain primary germplasm, or
from exchanges with other countries. Recent collections of
primary germplasm (still to be introduced to the ICG,T) aim
to increase the representation of the Criollo group. Click
here for a detailed description of the various cacao types.
Barbados Cocoa
Quarantine Station
The Cocoa Research Unit maintains a cocoa quarantine station in Barbados,
that aims primarily to facilitate the safe introduction of new
cacao accessions into Trinidad, for establishment in the ICG,T.
Utilisation
Selected cacao accessions with desirable agronomic traits are distributed
to cocoa-producing countries via intermediate quarantine at
the University of Reading, UK. In addition, some accessions
are used in pre-breeding programmes to accumulate desirable
genes, especially for resistance to Black Pod and Witches' Broom
diseases The main objective of such programmes is to produce
enhanced germplasm that will introduce resistance genes to conventional
breeding programmes in various cocoa-producing countries throughout
the world.
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