the common potato, solanum tuberosum ssp. tuberosum, is a tetrasomic tetraploid with a narrow genetic base. it has, however, approximately 200 related tuber-bearing species, both cultivated and wild, that are native to the american continent. many of these species, most of them diploid, are potential sources of genes of interest for breeding; however, they cannot be used directly in crosses with the common potato due to the presence of hybridization barriers. for approximately 30 years, the laboratory of genetics of the unidad integrada balcarce has carried out the morphological, genetic, biochemical and molecular characterization of argentinian wild potatoes, to identify hybridization barriers and to develop strategies to circumvent them for breeding. in the process, pre- and post-zygotic intra- and interspecific hybridization barriers -within and between ploidy levels- have been identifed, theoretical genetic models on the possible genetic control of these barriers have been developed, and interspecific hybrids have been generated through ploidy level manipulations. currently, the molecular bases of the pre-zygotic barriers are under study in the laboratory; a similar study for elucidation of the molecular bases of the post-zygotic barriers is at an advanced stage of development in mendoza, argentina, the morphological, genetic and molecular variability of natural populations samples classifed as pure species and the meiotic abnormalities detected in these and in natural hybrids, have led us to propose that the species concept in the wild potatoes should be revised in the light of these genetic findings.