In vitro rooting of Gladiolus microshoots

The present investigation was carried out to study the in vitro rooting in gladiolus shoot culture. Microshoots regenerated from inflorescence stalk of four gladiolus cultivars viz., Pusa Archana, Pusa Kamini, Pusa Urmil and Pusa Rangmahal were proliferated on multiplication media (MS+0.5 mg/l BAP + 0.5 mg/l KIN + 0.2 mg/l GA₃). Shoots derived on multiplication media were separated and transferred to rooting medium. For standardization of the techniques for in vitro rooting, effect of different media composition, rooting hormones i.e. Indole Butyric Acid (IBA) and sucrose levels were studied. Root induction occurred on all the media tried for rooting. However, the best medium for rooting was found to be full MS + 1 mg l⁻¹ IBA supplemented with 2–3% sucrose. Medium full MS + 1 mg l⁻¹ IBA was able to show maximum rooting per cent (88.95) while half-strength MS + 2 mg l⁻¹ resulted in earliest (11.79 days) root induction. Highest number of roots per shoot (16.54) was observed in medium with full MS + 2 mg l⁻¹ IBA. Regarding sucrose level, maximum rooting (92.54%) was recorded at 3 per cent and beyond this rooting per cent declined. Earliest rooting was observed in 3 per cent sucrose and after that it was increased. Number of roots per plant was more at 2 and 3 per cent sucrose. Further increase in sucrose level resulted in decrease in root number. Mean length of roots per shoot followed the same trend as to that of root number. Longest root (4.53 cm) was observed at 2 per cent sucrose and was found at par with 3% sucrose (4.24 cm). Further increase in sucrose showed a continuous decrease in mean root length. Shoots growing on the medium containing 2–3 per cent sucrose showed maximum root induction. At sucrose concentration higher than 3 per cent, the rooting was decreased with subsequent increase in sucrose level. The same trend was found with number of roots and root length.