Abstract: Interspecific somatic hybrids of black mustard and cauliflower were produced by asymmetric somatic hybridization to introduce disease-resistance genes of wild species into Brassica crops. Hypocotyl protoplasts of Brassica oleracea var. botrytis, genotype 0307, possess high regeneration capacity. B. nigra, genotype St.461, shows resistance to black rot, black leg and clubroot diseases . Hypocotyl protoplasts of 0307 were fused with UV-irradiated mesophyll protoplasts of B. nigra by the PEG method. Approximately 170 regenerated plants were obtained, and 30 of 40 plants were verified as somatic hybrids by morphological observation, and with RAPD and sequenc e-related amplified polymorphism (SRAP) molecular markers. Chromosome analys is showed 23% of the hybrid plants with fewer than 34 chromosomes , the sum of donor and recipient parents. Flow cytometry revealed most of the hybrid plants with DNA content two to four times greater than that of the fusion recipient but 20% with a content less than that of the sum of donor and recipient parents.