Determination of a steviol glycoside contents in stevia plants grown in different regions of Turkey

In this study, leaf characteristics (width, height, width/height ratio), dry leaf yields and steviol glycosides content of 4 different Stevia plants from Stevia Rebaudiana Bertoni (BRT1, BRT2 ve BRT3) and Stevia morita II (MRTII) grown in Mediterranean, Black Sea and Marmara regions were examined during the growing period. It was determined that the height of the seedlings of stevia varieties reached 74.00-101.50 cm at the end of growth-development stage. Total dry leaf yield of Stevia cultivars ranged between 333.96-624.00 kg/da and the highest total dry leaf yield was determined in Stevia Rebaudiana Bertoni (BRT3 - 624.00 kg/da) obtained from Burhaniye and grown in Mediterranean Region. The lowest total dry leaf yield was found in Stevia morita II (333.96 kg/da) grown in Marmara Region. Total Steviol Glycoside (TSG) content of Stevia cultivars was found between 11.90-17.76%, and Stevioside and Rebaudioside A content ranged between 1.44-8.45% and 3.42-13.98%, respectively. In terms of TSG content, the best Stevia cultivar was found in Stevia morita II cultivar (TSG 17.76%, Rebaudioside A 13.98% and Stevioside 1.98%). It is determined that our country is a suitable region in terms of soil structure and climate-ecological conditions in terms of Stevia cultivation and adaptation of Stevia morita II cultivar (MRT II) is easier, its harvest period is shorter and steviol glycoside content is higher variety.