High frequency of shoot regeneration from hypocotyls and stem segments of Antirrhinum majus (Snapdragon)

A broadly applicable direct shoot regeneration method from hypocotyls and stem explants has been developed for six cultivars of Antirrhinum majus L. In order to establish a stable and high frequency of shoot regeneration system, leaves, hypocotyls and stem explants of six cultivars were tested with 72 combinations of auxin ( naphthaleneacetic acid ( NAA) or 3- indoleacetic acid ( IAA)) and cytokinin ( 6- benzylaminopurine ( BA) or zeatin ( Z)). A few adventitious shoots were directly regenerated from hypocotyl segments of cv. Orchid on MS medium with NAA+ BA, IAA+ BA, NAA+ Z and IAA+ Z. High frequency of direct shoot regeneration was obtained from hypocotyl segments on MS medium with 0.05, 0.1 or 0.25 mg l(-1) NAA+ 2 mg l(-1) Z and 0.5 mg l(-1) IAA + 2 mg l(-1) Z. Finally, stable and high frequency ( 92 - 100%) of shoot regeneration with more than 10 adventitious shoots per explant was achieved from the hypocotyls and stem explants of all six cultivars on MS medium with 0.25 mg l(-1) NAA + 2 mg l(-1) Z. The shoots emerged directly from the hypocotyls and stem segments 4 weeks after culture initiation.