Standardization of sterilization protocol for explants and its suitability for direct organogenesis in tuberose cv. Arka Vaibhav

A study was carried out to standardize the sterilization protocol for different explants (terminal stem scale,immature flower bud and tepal segment) and to select the suitable explant for the direct organogenesis of tuberose cv. Arka Vaibhav. The highest survival per cent (100) and uncontaminated cultures (0.00) of terminal stem scale explant was observed in pre-treatment with overnight soaking of terminal stem scale in the solution comprising carbendazim (0.1%), chlorothalonil (0.05%) and myristyl trimethyl ammonium bromide (cetrimide) (0.05%) and subsequently surface sterilization with 70% ethanol (1 min), 4% sodium hypochlorite (10 min) followed by 0.1% HgCl2 (15 min). The explant immature flower bud recorded the highest survival per cent (100) and maximum aseptic cultures in the treatment T1 comprised of 1.0 drop Tween-20 + 70% ethanol (30 sec) and 1% sodium hypochlorite (3 min). Pre-treatment of tepal segment explant in 0.1% carbendazim (30 min) solution followed by surface sterilization with combination of 1.0 drop Tween-20 + 70% ethanol (30 sec) followed by 1% sodium hypochlorite (3 min) registered 91.66% of survival with the minimum contamination (10%) in the treatment. Among the three explants used, the terminal stem scale was found suitable for direct organogenesis with early greenness (5.72 days) and highly responsive to shoot induction (100%) in MS medium supplemented with 4 mg/L BAP + 0.1mg/L IAA. Other two explants viz., immature flower bud and tepal segment failed to respond for direct organogenesis by shoot induction instead produced profuse callus.