Selective breeding of genotypes with high content of rebaudioside A and stevioside diterppene glycosides in Stevia rebaudiana Bertoni

This study, conducted in Antalya, Turkey in 2014-2016, aimed to determine the genotypes with a high rebaudioside A/stevioside ratio and a high amount of rebaudioside A and stevioside in Stevia rebaudiana Bertoni and to reveal superior candidate varieties by the clone selection method. The study started with 200 genotypes in the first year, then the stem cuttings from 40 genotypes selected in the second year accordance with the obtained data were grown in row (A clones) and the 10 genotypes (B clones) selected from the clones in the third year were grown in three replicated according to the completely randomized block design. Four plants with superior characteristics were selected (C clones) in accordance with the criteria for the evaluation of the results. Row and intrarow spacing were 60 cm X 40 cm with all the clones per plot. Genotype 82 was regarded as a candidate with superior characteristics in terms of the amount of rebaudioside content. Genotype 109 was noteworthy for stevioside alone. Genotype number 133 was considered as not only high in the amount of diterpene glycosides but also as an industrial material suitable for processing and production due to the fact that the agronomic properties were above average during the study. As number 196 was determined to be high in terms of the amount of genotype stevioside and rebaudioside, it was selected as a variety candidate.