| 12 local B. oleracea species were examed for their protoplasts culture abilities to obtain more genotypes as receptors for protoplast fusion research. One cauliflower cultivar, "AoXue No.1", showed a high proroplasts dividing and plants regeneration capacity, and could be used in further works for somatic hybridization. Results also revealed that the shoot regeneration ability of the genotype was more fit as a standard for receptor selection than the frequency of cell division and callus formation. Asymmetric protoplast fusion between Brassica. oleracea L.var. botrytis and Brassica spinescens was taken for transferring of wild resistant traits into B. oleracea. Brassica spinescens possesses desirable characteristics such as high photosynthetic efficiency, resistance to white rust (caused by Albugo candida), resistance to aphid and alternaria blights(caused by Alternaria brassiceae) and tolerance to salt stress . PEG-induced asymmetric fusions were performed between mesophyll protoplasts of Brassica spinescens irradiated with UV and hypocotyl protoplasts of B. oleracea L.var botrytis, and 379 regenerated plants were obtained. POX isozyme analysis was taken in 120 plants , and 23 of them showed hybrid characters. RAPD marker detection further approved the hybrid inbeing of 17 plants. The relative nuclear DNA content of the hybrids measured by flow cytometry (FCM) showed that the 17 analyzed plants had a DNA content from tetraploidy to octoploidy. Influence of UV doses on the callus formation ability had been tested, and the results showed that the maximum UV dose for Brassica spinescens was 0.0750J/ cm2.
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