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 high regenerative capacity was tissue-dependent. Developmental polarity (apical and basal ends) of the explants appeared to play a regulatory role in shoot morphogenesis in this system. High-frequency shoot regeneration was obtained with N-6-benzyladenine or thidiazuron-supplemented media. Delayed and reduced regenerative ability of cultures in air-tight vessels and the dramatic suppression of shoot regeneration in internodal explants by the ethylene precursor 1-aminocyclopropane-1-carboxyjic acid implicate a possible involvement of ethylene in shoot morphogenesis in this, species. Rooting of regenerated shoots of B. oleracea, occurred readily on alpha -naphthaleneacetic acid-supplemented media. Rooted plantlets were successfully established in soil and developed normal fertile flowers and viable seeds.