The International Cocoa Genebank, Trinidad (ICG,T) contains 2300 accessions representing a broad range of diversity and geographic origins. This study was undertaken to examine the phenotypic relationships in a diverse sample of 600 cacao accessions from the Genebank. The major objectives were to test the applicability of the accepted nomenclature, viz., the definition of classes, as well as to elucidate the relationships between wild and cultivated germplasm and among accession groups. This will facilitate efficient utilisation, management and improvement of cacao genetic resources through the identification of potentially heterotic groups. In addition, information on morphological variation may be considered along with allelic richness or gene frequencies in selecting core collections, and when formulating strategies for future collections in the wild. Considerable phenotypic variation (high coefficients of variation and Shannon Weaver Diversity Index values) in the germplasm studied was found, and the main groups of cacao were clearly separated. Wild cacao was differentiated from cultivated types by all of the quantitative descriptors except pod length. Recognised genetic groups (Trinitario and Forastero) were discriminated by several quantitative traits including sepal length, cotyledon weight, length and width, and pod index. Principal Component Analysis differentiated among 14 accession groups according to geographic origin and genetic grouping. Cotyledon weight, length and number, pedicel column colour, mature pod ridge colour, sepal length, pod basal constriction and surface texture, and ovule number accounted for most of the variation recorded. The observed improvement in the cultivated germplasm, in terms of agronomic traits such as seed weight and pod index, attests to the success of past selection activities. This apparent improvement (particularly among Refractario germplasm) appears to be accompanied by increased style length, a finding that warrants further study. The reduced diversity in sepal length, ligue width, ovule number, and cotyledon length in the cultivated compared to the wild germplasm is consistent with the narrowing of the genetic base in the former. These results have significance for cacao breeding programmes, conservation and future collecting strategies.

The history of cocoa and chocolate including the birth and the expansion of the chocolate industry was described. Recent developments in the industry and cocoa economy were briefly depicted. An overview of the classification of cacao as well as studies on phenotypic and genetic diversity was presented. Cocoa agronomic practices including traditional and modern propagation techniques were reviewed. Nutrition-related health benefits derived from cocoa consumption were listed and widely reviewed. The specific action of cocoa antioxidants was compared to those of teas and wines. Effects of adding milk to chocolate and chocolate drinks versus bioavailability of cocoa polyphenols were discussed. Finally, flavor, sensory, microbiological, and toxicological aspects of cocoa consumption were presented.

The International Cocoa Gene bank, Trinidad, is an international cacao (Theobroma cacao L.) germplasm depository that conserves nearly 2500 accessions in its field collection. A portion of this germplasm was characterized for phenetic diversity with morphological descriptors from the International Board for Plant Genetic Resources cacao descriptor list. Data for 28 quantitative and 26 qualitative descriptors were obtained on 100 accessions representing 24 populations. Associations among the accessions were examined by hierarchical average linkage cluster analysis. Variances of the standardized values were computed for the quantitative descriptors. The diversity and evenness of the qualitative descriptors were assessed with the Shannon-Weaver diversity index (SWDI). The variances and the Shannon-Weaver diversity indices summarized the direct contributions of the quantitative and qualitative descriptors to the similarity measure. The variances of the standardized quantitative descriptors ranged from 0.03 for flower ligule length to 0.07 for fruit husk weight. About 75% of the fruit and bean descriptors had variances greater than 0.045, compared to 17% for the flower descriptors, indicating a relatively higher discriminative value of the former. Normalized SWDI values greater than 0.50 were obtained for 69% of the 26 qualitative descriptors. Eighty percent of the flower descriptors had SWDI values greater than 0.50, compared to 60% for those of the fruit and bean. Cluster analysis indicated rich phenetic diversity in this sample of germplasm. At the 75% level of similarity, the accessions were grouped in 11 clusters, each containing two or more accessions. Nine accessions were ungrouped. This diversity should prove useful for breeding programs. The observed link between geographic origin and accession grouping suggested that it is necessary to collect and conserve germplasm representing a broad geographic range.

Population structure of the old Trinitario cacao (Theobroma cacao L.) in Trinidad was evaluated from the 35‐microsatellite multilocus profile of 32 relict clones from abandoned cocoa estates in Trinidad (TRD) and 88 Imperial College selections (ICS) clones conserved in the International Cocoa Genebank, Trinidad. Ancestry was derived by comparison to 34 representative genotypes of Criollo, Central American, and Lower and Upper Amazon origin. The 154 individuals separated into four populations in this study, labeled Population 1—Upper Amazon; Population 2—Ecuadorian; Population 3—Lower Amazon; and Population 4—Trinitario. Over 90% of the individuals demonstrated 70 to 99% membership to their respective populations. The ICS and TRD clones formed a genetically homogenous group, 84% of which clustered in Population 4 with clones of pure Criollo descent. Another 10% clustered in Population 1 containing clones of Upper Amazon descent. The cacao population of Trinidad is genetically different from clones of Ecuadorian and Lower Amazon descent, Populations 2 and 3, respectively. The 10 most discriminating loci for each population were different as shown by polymorphism information content values for each of the 35 microsatellite loci. This is the first report to provide a strong genetic basis for the industry flavor distinction of Trinitario and Ecuadorian cacaos. These findings significantly impact germplasm fingerprinting and curatorship and maintenance of industry flavor classes while breeding for disease resistance in cacao.

The primary source of cadmium in cocoa beans has been linked to its direct uptake by the cacao plant from cadmium contaminated soils. This research was conducted to evaluate and interpret significant relationships between cadmium levels in tissues of the cacao plant and soils from cocoa-growing areas in Trinidad and Tobago. Total (HNO3-extractable) concentrations of cadmium in both tissues and soils were determined. The levels of cadmium measured varied in the order: leaves > pods > shells > nibs > soil. Cadmium levels in all the cacao tissues analyzed were significantly (p < 0.05), positively and strongly correlated with each other. Additionally, significant (p < 0.05) positive relationships were also identified between Cd in cacao tissues and corresponding total HNO3-extractable Cd levels in soils. These findings suggest that they can possibly be used as predictive tools for assessing Cd levels in cacao.