Abstract: The protoplasts were isolated from the leaves of Solanum tuberosum clones 3 # and 8 # (2n =48) , which were derived from cv. ‘Zhongshu 2’, and dipliod species S . chacoense (2n = 24) . The PEG and electric fusion methods were employed for looking into their effect s on the protoplast fusion. The results showed that no much difference existed in the fusion efficiency between the two methods , but higher cell platingf requency and a stronger plant differentiation ability of callus were observed in elect rofusion. Among 100 plants differentiated in earlier stage , 97 showed somatic hybrids by RAPD marker detection. Further ploidy level analysis with flow cytometry demonst rated that 52.6 % were hexaploids , 14.4 %octoploids , 14.4 % amphiploids and 18.6 % mixoploids. Cytoplasm recombination of the somatic hybrids were investigated using a specific chloroplast SSR primer NTCP29 , The result s indicated that most of the hybrids contain the chloroplast from one of the fusion parents. Only 16.5 % of the hybrids combined the two parental chloroplasts.

Key words: Potato, Protoplast fusion, Somatic hybrids, Genetic analysis