Variability in cacao accessions from the Brazilian, Ecuadorian and Peruvian Amazons based on molecular markers

The objective of this work was to study the genetic variability of 19 clonal accessions of Theobroma cacao L. from the Brazilian, Ecuadorian, and Peruvian Amazons, based on RAPD and microsatellite markers. Six primers were used to obtain the RAPD markers and six pairs of primers for the microsatellite loci. The amplification products were submitted to electrophoresis on 1.2% and 3.0% standard agarose for RAPD and microsatellite markers, respectively. The generated molecular markers were analyzed separately, by transformation into numeric matrices, whereupon the genetic distances were calculated and the cocoa accessions grouped. The six primers used in each technique generated 56 RAPD and 45 microsatellite markers. In the cluster analyses, the groups involved accessions from different origins, with no clear evidence of regionalization of the genetic variability. The high genetic variability found in this work confirms the importance of the Amazon basin for germplasm collection.