Micropropagation studies in "single" vs. "double" types of tuberose (Polianthes tuberosa L.).

Terminal or axillary stem scale sections from P. tuberosa cultivars Shringar (single type) and Suvasini (double type) were disinfected with 1000 ppm Bavistin [carbendazim], 1000 ppm Kavach [chlorothalonil], and 500 ppm Cetrimide, singly or in combination, before sterilization with 0.1% HgCl2 for 10-15 minutes. The explants were cultured in Murashige and Skoog's (MS) medium containing 3% sucrose and 0.25% phytagel, and autoclaved at 121 deg C for 15 minutes. The shoot tips from sprouted explants were transferred into a medium containing 2 or 4 mg BAP [benzyladenine]/litre singly or in combination with 0.1 mg IAA/litre. The regenerated shoots were transferred into 1/2 MS medium containing 0.5 or 1.0 mg IBA, 0.5 mg IAA, or 0.25 mg IAA + 0.25 mg IBA/litre. Treatment with Bavistin + Kavach + Cetrimide overnight followed by treatment with HgCl2 for 15 minutes resulted in the highest percentage of axenic cultures using axillary (23.3-26.6%) and terminal (30.0%) scale s ections. Cytokinin induced multiple shoot formation; however, the addition of auxin increased the regeneration response. A multiple shoot induction of 100% was obtained with 2 mg BAP + 0.1 mg IAA/litre. Shoot length increased with the increase in BAP level. A rooting percentage of 100%, along with the highest average number of roots (16.70 in Shringar and 15.8 in Suvasini), was recorded for 0.2 mg IAA + 0.25 mg IBA/litre. The longest roots (1.39 cm in Shringar and 1.33 cm in Suvasini) was obtained with 0.5 mg IBA/litre. Suvasini exhibited greater regeneration potential than Shringar. The rooted plantlets were hardened in polybags containing autoclaved soil, sand, and soilrite (1:2:1). The hardened plants showed 100% survival in pots