Comparative Study on Callus Induction, Proliferation and Plantlets Regeneration In Two Cultivars of Stevia rebaudiana Bertoni – The Only Non Caloric Natural Sweetener

The present report describes a comparative study for plant regeneration through callus morphogenesis in two different cultivars ‘CIM madhu’ and ‘CIM mithi’ of S. rebaudiana. The leaf explants were cultured on MS medium supplemented with IBA (1.0-4.0 mg/l) in combination with BAP (0.2 mg/l) for callus induction. Among the various tested combinations for shoot regeneration, maximum multiplication was recorded with MS + Kn (2.0 mg/l) + NAA (0.2 mg/l) + ADS (40 mg/l). Half-strength MS medium with IBA (0.2 mg/l) + AC (100 mg/l) was the best medium for the in vitro rooting of regenerated shoots. A comparison of different hardening media was also studied between two cultivars. The micro-plantlets hardened in plastic pots filled with sand: soil: vermiculite (1:2:1), covered with transparent polythene bags took minimum time to glass house transfer with maximum survival rate. CIM-madhu showed good callus induction, proliferation and regeneration ability in comparison to CIM-mithi. In comparison, higher rooting percentage was obtained in CIM-madhu with 97 % survival rate. The ability of ‘CIM-madhu’ to induce callus and regenerate successful plantlets under these conditions suggests that this cultivar is moderately suitable for micropropagation purposes.