Agarose plating and a bead type culture technique enable and stimulate development of protoplast-derived colonies in a number of plant species.

Two novel techniques improve division and colony formation from protoplasts: 1) Plating in agarose stimulates colony formation of protoplasts from a wide range of species. Protoplasts from Nicotiana tabacum developed to colonies from lower initial population densities in agarose than in agar or liquid. Protoplasts from Hyoscyamus muticus which do not divide in agar divided and formed colonies in agarose at higher efficiencies than in liquid medium. 2) Culture of gel embedded protoplasts in large volumes of liquid medium on a gyrotatory shaker ('bead culture') further improved plating efficiencies in some species (e.g. Lycopersicon esculentum and Crepis capillaris) and enabled sustained proliferation of protoplasts which had not previously developed beyond the few cell colony stage (Brassica rapa and a mutator gene variety of Petunia hybrida). The combination of 'agarose plating' and 'bead culture' dramatically improved plating efficiencies of protoplasts in all species tested.