A study on the genetic variability of Bolivian cocoa in the northern La Paz region received recognition from the Executive Committee of Bolivian Universities, among the three best papers presented at the Second National University Fair for Research, Science and Technology, held between August 24th and 26th in the city of Sucre. The study was conducted by Daniela Arteaga and Ximena Sandy and promoted by Wildlife Conservation Society and Helvetas Swiss Intercooperation, in coordination with the Institute of Scientific and Technical Research of the Police University (IITCUP).
In the Amazonian forests of northern La Paz varieties of high organoleptic quality cocoa (taste and aromatic qualities) naturally evolved, which have recently gained national and global recognition. Traditionally, indigenous communities gather cocoa from the forest, and also grow it from seeds in agroforestry systems, preserving habitat for a variety of wildlife species.
For the study, 19 populations of cacao were analyzed (11 wild stands and 8 cultivated) from various communities of the Tacana and Lecos Larecaja Indigenous Territories, and the municipalities of Guanay and Mapiri. A total of 201 cocoa plant leaf tissue samples were processed. Through the application of microsatellite markers (SSRs type), information on genetic relationships were obtained at the individual, lineage and population levels. Moreover, by sequencing the trypsin inhibitor, the main component of the cocoa bean, the cacao populations’ genetic evolution was analyzed.
Results of the average analysis of genetic structure (index of genetic diversity, heterozygosity and polymorphic information content), show that populations of wild cacao represent twice the average of cultivated populations, meaning they have greater genetic variability. This was especially relevant in some stands along the Beni River (Isla de Oro, Tacana) and Madidi River (Ojaki). Cultivated populations in Villa Alcira (Tacana) and Chavarria (Lecos of Larecaja) have a recent process of domestication. On the contrary, cultivated cacao populations in Tutilimundi, Candelaria and Michiplaya (Lecos of Larecaja) have already gone through processes (natural or induced) to select varieties.
The analysis of the phylogeny or evolutionary history of the 19 populations of cacao shows the relationships between them, stressing that cultivated populations originate from populations of wild cacao as a result of the traditional process of wild cacao domestication by indigenous peoples since pre-Hispanic times. Knowing the genetics of wild populations and their relationship with cultivated populations opens opportunities to identify promising varieties that could boost productivity in Bolivia, and also consolidate quality cocoa markets.