Plant regeneration from protoplasts of a wild lettuce species (Lactuca saligna L.).

Protoplasts isolated from young, unexpanded leaves of the wild lettuce species, Lactuca saligna, divided to give colonies, when plated at low density in KP8 medium solidified with 1% (w/v) agarose. Sustained colony development was dependent upon the incorporation of the bead culture approach. Plant regeneration, via organogenesis, followed the transfer of colonies firstly to K8 medium and then to M/S medium supplemented with IAA and 6-BAP, both solidified with 1% (w/v) agarose. Excised shoots were rooted on agar-solidified M/S medium lacking phytohormones. The potential of this species as a source of race-non-specific mildew resistance for transfer into lettuce (L. sativa) via somatic hybridisation is discussed.