Unrooted phylogenetic tree of 312 tobacco accessions constructed on the basis of 49 microsatellites loci using Cavalli-Sforza's genetic distance and the neighbor-joining method. Clades represent accessions defined as "Burley" (light blue), "Primitive" (blue), "Dark" (black), "Cigar" (violet), "Oriental" (green) and "Flue-Cured" (yellow). Accession of "Other" and unknown types are shown as white circles. Clades are color coded according to the predominant tobacco type included, and when this was not possible, they are indicated with black lines. Numbers refers to the order in the list of the 312 accessions, provided as online Additional file 1.