Molecular characterization of national cocoa collection from the leading traditional growing areas in Ecuador

Abstract

Ecuador is the leading producer and exporter of fine cocoa, with plantations over 80 years old, preserving distinctive aroma and flavor characteristics. The research objective was to screen the genetic variability of a collection of National cocoa from Ecuador's leading traditional cocoa growing areas, denominated as Centennial National Cocoa Plants (CCNC). This germplasm collection with 243 accessions was analyzed with 20 microsatellites (SSR) markers. DNA genotyping was highly informative, generating a total of 109 SSR alleles with an average of 5.5 alleles per locus. Only 0.8% of duplicate accessions were identified. The average genetic diversity obtained was 0.447, and the polymorphic content index was 0.414, which shows a high genetic diversity. The clustering, main coordinates, and population assignment analysis revealed that the samples are classified into two subpopulations (GN and GM), differentiated by their level of heterozygosity, with a fixation index value of 0.105. The results showed that microsatellite markers and statistical tools provide useful information that favors managing and conserving genetic variability in CCNC collection. Keywords: fine and aroma cocoa, Sabor Arriba, DNA genotyping, SSR markers