In the present study, wide hybridization was performed between ‘Whenzhou turnip’ (Brassica rapa L. em. Matzg.，2n=20, AA) and ‘purple kohlrabi’ (B. oleracea L. var. caulorapa DC, 2n=18, CC) by hand emasculation following tissue culture for hybrid seeds. A total of 2 hybrids were obtained through bud pollination and ovary culture, and 19 asexual seedlings were obtained through expanding propagation. Morphological analysis, cytological observation and RAPD molecular analysis identified the two strains as true hybrids of ‘Wenzhou turnip’ × ‘purple kohlrabi’, and then the novel allotetraploid rutabagas germplasm was obtained by chromosome doubling (AACC, 2n=38). The two hybrid lines were separated by stem color, and their root and stem were enlarged, but the degree was lower than that of the parents. The floral organs of allotetraploid were larger, anthers developed normally, and the pollen viabilities was higher. The new germplasm of allotetraploid rutabagas was obtained in present studies, which expanded the genetic background of rutabagas germplasm resources to a certain extent and laid a foundation for the research on the origin and evolution, genetic improvement, production and promotion of rutabagas.