Randomly amplified polymorphic DNA (RAPD) analysis was carried out to develop sufficient numbers of PCR-based genetic markers in two cultivated and four wild species of sections Cepa and Phyllodolon in Allium. Sixty random decamer primers were examined, generating large numbers of RAPD bands between the species. A total of 393 RAPDs were detected between the cultivated species, A. fistulosum and shallot (A. cepa var. ascalonicum). The number of RAPDs between A. fistulosum and the four wild species, A. altaicum, A. galanthum, A. oscaninii, A. vavilovii, was respectively 167, 269, 363, 365 and those between shallot and the wild species was respectively 454, 398, 390, 156. These RAPDs will be useful as genetic markers in the two sections. Some of the RAPDs were effective for identifying interspecific hybrids. The RAPD markers successfully confirmed the hybrid nature in ten kinds of F1 plants. Research was also done on the origin of A. wakegi which is well known as a natural hybrid between A. fistulosum and shallot. In 27 clones, species-specific RAPD markers proved the hybrid origin of this plant and that its parental plants are the above mentioned species. Further, the RAPD variations observed in shallot and A. wakegi indicate a polyphyletic generation of initial clones in this species.