In vitro cloning of stevia rebaudiana Bertoni to avoid verification and production of syn-thetic seeds

Abstract

Stevia rebaudiana Bertoni is an important medicinal plant; plant leaves are used as a source of non-caloric sweetener-stevioside, which is estimated to be 300 times sweeter than cane sugar. Seed germination of stevia is very low, so micropropagation is an essential prerequisite for stevia mass production and modification. Determined plant tissue culture conditions were applied to establish shoot cloning and synthetic seeds (synseeds) formation. Efficient shoot multiplication was established on MS medium with 0.25 mg/l BAP. While the best shoot formation frequency was obtained when nodal or shoot cuttings were sub cultured for the fifth time, addition of 1.7 mg/l of AgNO3 increased the values of shoot formation frequency and reduced verification. For production of artificial seeds, small nodal cuttings, about 3 mm long each, were coated using sodium alginate (4%) and CaCl2 (75 mM) solution as a gel matrix and a complexing agent, respectively. Shoot cuttings resulting from the conversion of synseeds or shoot culture were used to establish root formation on MS medium containing 1 mg/l IBA. Plantlets with extensive root systems were hardened and successfully established in the soil.