Part of the Neighbour-Joining tree based on Kimura 2-parameter for 164 grapevine entries belonging to Vitis spp. and rooted using as outgroup the accessions from V. labrusca , V. cinerea , V. berlandieri , V. rupestris and V. riparia species. In detail, only the branches showing the relationships among Vitis spp. and the interspecific hybrids are indicated (see Additional file 3 for the complete Neighbour-Joining tree). The branch labelled with V. vinifera accessions indicates the whole accessions of V. vinifera and includes also the putative hybrid 516_Tintoria that resulted to be indistinguishable from other cultivated grapevines. The numbers above the nodes represent the bootstrap support after 1,000 replicates.