In vitro flower induction in roses

Vegetatively propagated plantlets of six rose cultivars were induced to flower in vitro on media containing full-strength Murashige and Skoog (MS) inorganic salts, Gamborg's B5 organic elements with 400mgl(-1) myo-inositol, and different phytollormone combinations of 6-benzyladenine (BA) with alpha-naphtlialeneacetic acid (NAA) thichazuron (TDZ) with NAA; and zeatin (ZT) with NAA. The most efficient flower bud induction (49.1% and 44.1% was obtained on media supplemented with 0.5mg l(-1) (2.27muM) TDZ and 0.1mgl(-1) (0.54VmuM) NAA or 0.5 mgI(-1) (2.28muM) ZT and 0.1mgl(-1) (0.54 muM) NAA for cultivar Orange Parade. Scanning electron microscopy (SEM) showed that in vitro flower bud induction occurred mostly between 15 and 30 d in induction medium through the normal flower development processes. With TDZ and ZT as the best choice for flower induction in all six cultivars tested, different rose cultivars varied in their responses to phytohormone treatments. Our stud), also revealed that the total time from original culture and subculture time before flower induction were two very important factors for in vitro flower induction. Plantlets 156-561 d from original culture and Subcultured for 45 d were the best for flower induction.