For many crop plants, germplasm can be stored in the form of dried seeds and at low temperature (i.e. so-called ‘orthodox’ seed storage) but this is not possible with cacao whose seeds are recalcitrant, i.e. they normally germinate as soon as they are removed from the pod and will not survive the drying process and/or storage at low temperature. Therefore, cacao germplasm has to be maintained as living trees, either ex situ in field genebanks or in situ in farmers’ fields or in protected areas such as nature reserves.  Although conservation in the form of trees has the advantages that the growing material can readily provide budwood, seed or pollen needed for utilisation, as well as being available for characterisation and on-going evaluation of their potential, such collections have associated risks and are costly to maintain. 

The risk of genetic erosion through losses due to pests, diseases, drought, fire, adverse environments and human causes has to be minimised by, among other activities, ensuring that each accession of conserved material is represented by sufficient individuals, that each is adequately duplicated for safety purposes between genebanks, and that adequate resources are available to manage and secure the collection for the long-term.  

Recent developments in cryopreservation technology – i.e. storing germplasm in the form of tissue, cell suspensions or as embryos, in or over liquid nitrogen at –196°C – offers a complementary way to conserve cacao.  It has been demonstrated that cacao tissue samples, such as induced staminode tissue and somatic embryos, can be cryoprepserved and then regenerated into whole plants through a tissue culture process.  Further research may be needed to ensure that such cryopreserved material maintains its genetic integrity through the tissue culture process and while being stored at low temperature, and that it subsequently behaves normally under field conditions.  Storage of frozen pollen samples may offer an additional way to conserve cacao, though the parent clone’s genetic identity would not be maintained.

Whichever method is used to conserve germplasm it is essential that before conserving the material appropriate steps are taken to minimise misidentification problems arising in the genebank or cryopreserved collection.  This is particularly important for crops such as cacao, where the costs involved in medium- and long-term conservation are high.  It is known that mislabelling occurs in cacao genebanks, as it does in the genebanks of many other crops.  In the past, problems have arisen, for example, due to outgrowths of the rootstock material eventually replacing the scion, self-sown seedlings establishing themselves in clonal plots, inaccurate labelling and damage/loss of labels and maps.  Strategies to confirm identities of clones through morphological and genetic characterisation, and to deal with any misidentified material are being developed and progress is being made in implementing them in several genebanks.