In Vitro Propagation and Conservation of Stevia Rebaudiana Bertoni

Abstract

Experiments were conducted on in vitro culture of Stevia rebaudiana Bertoni, an important non-caloric sweetening herb to explore its potential for micro-propagation. Nodes, internodes and leaves of pot grown mature plants were used as explants and experiments were based on surface sterilization; direct shoot proliferation; callus formation; indirect shoot proliferation from callus and root proliferation of induced shoot. Normal process of tissue culture technique was followed for in vitro culture of the different explants. Different concentration of Auxins (IAA, IBA, NAA, 2,4-D) and Cytokinin’s (SAP, Kn) were used individually or in combinations in the culture media as growth regulator supplements. For surface sterilization, 2 minutes of Mercuric chloride (HgCb) treatment was found the most effective for leaves and 2.5 minutes for nodes and internodes. Nodes showed the highest percentage of direct shoot proliferation compared to internodes. BAP (2.0 mg/l) + NAA (0.2 mg/I) was the best combination for direct shoot proliferation. When this combination of growth regulators was used in the culture media, highest percentage of proliferated shoots from nodes was 92.84 ± 0.45, average number of shoots per explant was 4.16 ± 0.28 and average length of the longest shoot was 2.67± 0.98 cm. In same combination, highest percentage of proliferated shoots from internodes was 84.87 ± 0.62, average number of shoots per explant was 3.95 ± 0.34 and average length of the longest shoot was 2.78 ± 0.43 cm. But internodes showed the highest percentage of callus formation compared to nodes and leaves. 2,4-D (2.5 mg/I) + NAA (1.5 mg/I) was the best combination for callus