PLANT-REGENERATION FROM COTYLEDON AND CELL-SUSPENSION PROTOPLASTS OF APPLE (MALUS X DOMESTICA CV STARKRIMSON)

Protoplasts were isolated from field and in vitro-grown leaves, cotyle dons and cell suspension cultures (of ovule callus origin) of the scio n apple cultivars Starkrimson, Rainier, Qiujin and Liaofu. Fast-growin g calluses were obtained from leaf, cotyledon and cell suspension deri ved protoplasts of the four genotypes. The best proliferation response s were obtained from cell suspension protoplasts. For all genotypes te sted, nodular calluses were obtained from protoplasts that had origina lly been cultured on K8P medium, but only those of cultivar Starkrimso n underwent organogenesis. In this cultivar shoot buds were produced o n callus derived from both cotyledon and cell suspension protoplasts a nd complete plants. This is the first example of whole plant regenerat ion from protoplasts isolated from an undifferentiated tissue in apple .