Steviol glycosides induced in vitro from three stevia genotypes successfully planted in Egypt

Stevia is considered a promising plant in Egypt according to the suitable soil and climate. Vegetative propagation of stevia is needed to encourage spreading distinguished genotypes in Egypt (Morita, Eirete and Brazilian genotype). For this target, micropropagation could be a beneficial new technique. Our study aimed to establish a tissue culture protocol for three genotypes of stevia plant in Egypt. Moreover, salinity tolerance assessment had been done for the three genotypes. In this investigation, Benzylaminopurine (BAP) with various concentrations (0.00, 0.25, 0.50, 1.0 mg/l) was studied for multiplication as well as various medium strengths. In addition, Indole butyric acid (IBA) with concentrations of 0.0, 0.25, 0.5, 1.0 and 2.0 mg/l were studied for rooting stage. Various concentrations of NaCl were used to study the tolerance ability of the three genotypes used in this research; 0.0, 25, 50 and 100 mM. Our results assured that enhancing multiplication rate had been taken place with all used concentrations of BAP comparing with the control (free of BAP). Meanwhile, 1.5 of Murashige and Skoog medium (MS) strength enhanced all growth parameters. Rooting percentage as well as root number highly rose at 1.0 mg/l IBA. Morita genotype showed superior response in multiplication and rooting stage followed by other genotypes. According to salinity tolerance, Eirete was the most tolerated genotype. Nutrient, carbohydrates and proline contents of the three stevia genotypes were determined according to salinity stress. In addition, HPLC analysis showed steviol glycosides in vitro production and their raising production according to salinity stress.