Ploidy variation in Solanum brevidens plants regenerated from protoplasts using an improved culture system

Plating efficiency of cultured protoplasts of Solanum brevidens increased to c. 10% after the addition of 5⋅0 mol m−3 glutamine to the culture medium. Growth of protoplast-derived colonies at densities of 20 colonies cm−3 was obtained by lowering the auxin content alter 4–6 d. A sample of 50 protoplast-derived plants was examined for chromosomal variation. Twelve plants were diploid (2n=24), 26 were tetraploid (2n=48) and 12 were aneuploid at the tetraploid level (2n=48±). Tetraploid and aneuploid plants had broader leaves and set fewer or no seeds compared to the diploid regenerants which were similar in gross morphology and seed set to control plants.