Induction, identification and characterization of polyploidy in Stevia rebaudiana Bertoni

Stevia rebaudiana Bertoni produces sweet steviol glycosides; these are regarded as the most promising substitute for sucrose and have a wide range of applications with high economic value. To improve steviol glycosides yields, we established an efficient method for inducing polyploidy in S. rebaudiana. Treatment with 0.05% colchicine for 48 h or with 0.1% colchicine for 24 h efficiently induced polyploidy in germinating seeds and polyploidy could be accurately identified using flow cytometry. Most of the tetraploid S. rebaudiana plants exhibited apparent variations in cytological and morphological characteristics, and had higher contents of the two main steviol glycosides, stevioside and rebaudioside A, than the diploid controls. These tetraploid plants may be further selected for breeding purposes or micropropagated for commercial production.