Origin of some minor vegetatively propagated Allium crops studied with RAPD and GISH

Three vegetative crops of sect. Cepa in genus Allium (Top onion, French grey shallot and viviparous triploid onion) of suspected hybridogenic origin were studied with genomic in situ hybridization (GISH) and random amplified polymorphic DNA (RAPD) markers. Related wild and cultivated species were included in the analysis in order to assess their contributions to the genomes of the investigated species. In A. × proliferum, the parental chromosomes derived from A. fistulosum and A. cepa were unequivocally identified by GISH, proving the hybrid status of this crop. The French grey shallot proved to belong to A. oschaninii according to the RAPD analysis and the GISH results, it is clearly separate from the normal shallots of A. cepa var. aggregatum. Thus the grey shallots are a new crop species and can be considered as an aggregatum form of the wild progenitor species A. oschaninii. The triploid viviparous onion comprises mostly A. cepa derived DNA in its genome. A non-cepa component could not be attributed to any of the sect. Cepa species included in this study and is most likely derived from one of the species of this section not yet identified by molecular means.