A protoplast-to-plant system in chrysanthemum: differential responses among several commercial clones.

Plant regeneration has been obtained from Chrysanthemum mesophyll protoplasts. Of the twenty-nine clones studied, division was observed for eighteen clones, and coupled with colony formation for sixteen of them. Elimination of NH4NO3 from the culture medium greatly improved colony survival in culture. Calli were obtained from colonies of five clones, and for clone n(o) 42 buds were produced. Regeneration ability, for such protoplast-derived calli of clone n(o) 42, was retained over a prolonged culture period. The regenerated plants were successfully transferred to the glasshouse (4 to 5 months from protoplast isolation).