title: Insight into the wild origin, migration and domestication history of the fine flavour Nacional Theobroma cacao L. variety from Ecuador.
abstract: Ecuador's economic history has been closely linked to Theobroma cacao L cultivation, and specifically to the native fine flavour Nacional cocoa variety. The original Nacional cocoa trees are presently in danger of extinction due to foreign germplasm introductions. In a previous work, a few non-introgressed Nacional types were identified as potential founders of the modern Ecuadorian cocoa population, but so far their origin could not be formally identified. In order to determine the putative centre of origin of Nacional and trace its domestication history, we used 80 simple sequence repeat (SSR) markers to analyse the relationships between these potential Nacional founders and 169 wild and cultivated cocoa accessions from South and Central America. The highest genetic similarity was observed between the Nacional pool and some wild genotypes from the southern Amazonian region of Ecuador, sampled along the Yacuambi, Nangaritza and Zamora rivers in Zamora Chinchipe province. This result was confirmed by a parentage analysis. Based on our results and on data about pre-Columbian civilization and Spanish colonization history of Ecuador, we determined, for the first time, the possible centre of origin and migration events of the Nacional variety from the Amazonian area until its arrival in the coastal provinces. As large unexplored forest areas still exist in the southern part of the Ecuadorian Amazonian region, our findings could provide clues as to where precious new genetic resources could be collected, and subsequently used to improve the flavour and disease resistance of modern Ecuadorian cocoa varieties.
authors.affiliation: UMR AGAP, CIRAD, Montpellier, France.
authors.forename: Rey Gaston
authors.initials: RG
authors.lastname: Loor Solorzano
authors.forename: Olivier
authors.initials: O
authors.lastname: Fouet
authors.forename: Arnaud
authors.initials: A
authors.lastname: Lemainque
authors.forename: Sylvana
authors.initials: S
authors.lastname: Pavek
authors.forename: Michel
authors.initials: M
authors.lastname: Boccara
authors.forename: Xavier
authors.initials: X
authors.lastname: Argout
authors.forename: Freddy
authors.initials: F
authors.lastname: Amores
authors.forename: Brigitte
authors.initials: B
authors.lastname: Courtois
authors.forename: Ange Marie
authors.initials: AM
authors.lastname: Risterucci
authors.forename: Claire
authors.initials: C
authors.lastname: Lanaud
mesh_terms: D000483:Alleles; D005075:Biological Evolution; D002099:Cacao / Q000235:genetics* / Q000266:history*; D018556:Crops, Agricultural / Q000235:genetics* / Q000266:history*; D060146:Ecotype; D004484:Ecuador; D056426:Genetic Loci / Q000235:genetics; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D049668:History, 15th Century; D049672:History, 19th Century; D049690:History, Ancient; D018895:Microsatellite Repeats / Q000235:genetics; D009812:Odorants / Q000032:analysis*
chemical_list: D005819:Genetic Markers