Induction of polyploidy in stevia plants (Stevia rebaudiana Bertoni) using colchicine

In the present study, the effects of colchicine applications on polyploidization were investigated in the stevia, whose Latin name is Stevia rebaudiana Bertoni. In the study shoot tips of seedlings from tissue culture of the local stevia variety Levent 93, which has long plant height and leaf length, and wide and large leaves, and high rebaudiosit A/steviosit ratio and rebaudiosit A content were used as plant material. Colchicine (C22H25NO6), which is an alkaloid obtained from the meadow saffron (Colchicum automnale) was used as mutation material. The main aim of the study is to obtain tetraploidy stevia plants by doubling the diploid chromosome number. After the method to be used in the study was determined, it was planned to try a single dose and different application times. Studies conducted for this purpose were examined and 0,05% concentration of colchicine was determined. Stevia shoot tips were immersed colchicine solution for control, 1 hour, 2 hours and 4 hours. Result of the study, has been determined the viability rate (13,3-100%), the plant height (20-75 cm), the number of leaves per plant (16-60 pieces), the number of branches per plant (1-11 pieces) and the content of chlorophyll (9,7-26,9 spad) of stevia plants treated with colchicine. The ploidy levels in plants were determined by flow cytometer analysis. According to the flow cytometer analysis of the study tetraploidy plants were obtained. As a result of the evaluations, it was concluded that colchicine caused polyploidy in stevia.