SOMATIC EMBRYOGENESIS AND PLANT-REGENERATION FROM PROTOPLASTS OF SATSUMA MANDARINE (CITRUS-UNSHIU MARC)

Protoplasts were isolated from embryogenic calli of 'Satsuma' mandarin (Citrus unshiu Marc. cultivar 'Tokumori Wase') and cultured in Gellan gum-embedded Murashige and Tucker (MT) medium containing 40 mg l-1 adenine, 0.15 M sucrose and 0.45 M mannitol. The percentage of colony formation (plating efficiency) 40 days after culture was 46%, much higher than that in MT medium without adenine. Most of the colonies grew about 1 mm after 2 months of culture and were successfully transferred onto MT medium containing 5% lactose for embryoid formation. Five percent of the resulting embryoids germinated normally and grew into plantlets, 30-60 days after transplanting on MT medium containing 1 mg l-1 gibberellic acid, 3% sucrose and 0.2% Gellan gum. Plant regeneration from protoplasts was also obtained in other important selections, cultivars 'Miyagawa Wase' and 'Okitsu Wase', using the same methods.