High-frequency direct shoot regeneration and continuous production of rapid-cycling Brassica oleracea in vitro

An in, vitro method was developed for high-frequency shoot regeneration and continuous production of rapid-cycling B. oleracea in large numbers. The h igh regenerative capacity was tissue-dependent. Developmental polarity (api cal and basal ends) of the explants appeared to play a regulatory role in s hoot morphogenesis in this system. High-frequency shoot regeneration was ob tained with N-6-benzyladenine or thidiazuron-supplemented media. Delayed an d reduced regenerative ability of cultures in air-tight vessels and the dra matic suppression of shoot regeneration in internodal explants by the ethyl ene precursor 1-aminocyclopropane-1-carboxyjic acid implicate a possible in volvement of ethylene in shoot morphogenesis in this, species. Rooting of r egenerated shoots of B. oleracea, occurred readily on alpha -naphthaleneace tic acid-supplemented media. Rooted plantlets were successfully established in soil and developed normal fertile flowers and viable seeds.