Journal of Applied Horticulture. 2001: 3(2): 82-84

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

Krishnamurthy, K B; Mythili, J B; Meenakshi Srinivas

Division of Horticulture, University of Agricultural Sciences, Bangalore - 560 065, India.

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 degrees 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 sections. 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.