Location: Sustainable Perennial Crops LaboratoryTitle: The relic Criollo cacao in Belize- genetic diversity and relationship with Trinitario and other cacao clones held in the International Cocoa Genebank, Trinidad Author
Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2009
Publication Date: 1/14/2010
Publication URL: http://dx.doi.org/10.1017/S1479262109990232
Citation: Motilal, L., Zhang, D., Umaharan, P., Mischke, B.S., Mooleedhar, V., Meinhardt, L.W. 2010. The relic Criollo cacao in Belize- genetic diversity and relationship with Trinitario and other cacao clones held in the International Cocoa Genebank, Trinidad. Plant Genetic Resources: Characterization and Utilization. Available at http://dx.doi.org/10.1017/S1479262109990232. Interpretive Summary: Cacao is an important tropical tree crop since it is the source of cocoa butter and powder for the confectionery and chocolate industries. Genetic resources of cacao are important for breeding new cacao varieties and thus are of great importance for sustainable cacao production. A lack of knowledge about the genetic diversity in cacao limits the conservation and use of these new cacao resources. In the present study, we analyzed the population structure and genetic ancestry in 78 selections of a high quality heirloom cacao originally from Belize using DNA finger printing technology. The results showed that these cacao varieties are very closely related to each other. The genetic analysis also suggests that some of these materials may have been used to derive other high quality cacao from Trinidad. These results improve our understanding of the diversity within cacao and will help cacao researchers establish conservation priority. This information will contribute to a more efficient management of cacao germplasm and will improve the breeding of better cacao varieties. These results will be useful to plant breeders, germplasm curators and cacao farmers and will benefit chocolate consumers.
Technical Abstract: Cacao (Theobroma cacao L.) is native to the South American rainforest but it was domesticated in Mesoamerica. The relic Criollo cocoa in Belize has been well known in the premium chocolate market for its high-quality. Knowledge of genetic diversity in this variety is essential for efficient conservation and use of this relic cacao variety. Using thirty microsatellite markers, we characterized genetic diversity in 78 Belize Criollo accessions held in the International Cacao Genebank, Trinidad, and assessed their relationship with the Trinitario cacao and other genetic groups. The result shows that the Belizean Criollo materials have a low genetic diversity and low heterozygosity. Eleven distinctive clones were identified out of the 78 collected accessions. Results of ordination and cluster analysis supported putative ancestral contribution to the Trinitario cacao. However, results of Bayesian assignment and parentage analysis both suggest that the parentage contribution of the Criollo cacao to the ICS Trinitario is small. The information generated by the present study provides new insight in the origin of the Trinitario cacao. It will also be used to assist ex situ and in situ conservation of cacao landraces from Mesoamerica.