Coffee is one of the main agrifood commodities traded  worldwide. In 2009, coffee accounted for 6.1% of the value of Brazilian  agricultural production, generating a revenue of US$6 billion. Despite the  importance of coffee production in Brazil, it is supported by a narrow genetic  base, with few accessions. Molecular differentiation and diversity of a coffee  breeding program were assessed with gSSR and EST-SSR markers. The study  comprised 24 coffee accessions according to their genetic origin: arabica accessions  (six traditional genotypes of C. arabica), resistant arabica (six leaf  rust-resistant C. arabica genotypes with introgression of H?brido de  Timor), robusta (five C. canephora genotypes), H?brido de Timor (three C.  arabica x C. canephora), triploids (three C. arabica x C.  racemosa), and racemosa (one C. racemosa). Allele and polymorphism  analysis, AMOVA, the Student t-test, Jaccard's dissimilarity  coefficient, cluster analysis, correlation of genetic distances, and  discriminant analysis, were performed. EST-SSR markers gave 25 exclusive  alleles per genetic group, while gSSR showed 47, which will be useful for  differentiating accessions and for fingerprinting varieties. The gSSR markers  detected a higher percentage of polymorphism among (35% higher on average) and  within (42.9% higher on average) the genetic groups, compared to EST-SSR  markers. The highest percentage of polymorphism within the genetic groups was  found with gSSR markers for robusta (89.2%) and for resistant arabica (39.5%).  It was possible to differentiate all genotypes including the arabica-related  accessions. Nevertheless, combined use of gSSR and EST-SSR markers is  recommended for coffee molecular characterization, because EST-SSRs can provide  complementary information.
Alleles Coffea