Enhancement of Steviol Glycosides in Stevia (Stevia rebaudiana Bertoni) Through Induction of Polyploidy

Mutation and manipulation of ploidy were tried on stevia (2n=22) to develop higher content of steviol glycosides. Different stevia mutants were developed using Colchicine using 0.25%, 0.50%, 0.75%, 1.0%, 1.50%, and 2.5% and they were tested for their DNA content to ascertain the change in ploidy. Ploidy level was identified by flow cytometry analysis and steviol glycoside content in the leaves was determined by HPLC. Some polyploids showed two times increase in the percentage of stevioside as well rebaudioside-A, compared to control. Thus, induction of polyploidy in stevia confirmed the effectiveness of colchicines as a polyploidizing agent creating new variants with higher steviol glycosides (stevioside and rebaudioside-A) content contributing to crop improvement in stevia.