INDUCE GENETIC VARIABILITY AND SELECTION FOR SALT TOLERANCE IN STEVIA PLANT (Stevia rebaudiana, Bertoni)

Abstract

1. Plant materials The present study was conducted at the Plant Tissue Culture Laboratory, Sugar Crops Research Institute, Agricultural Research Center (ARC), Giza, Egypt during the period from 2014 to 2017. Seedlings of Stevia rebaudiana var. Spanti kindly obtained from Sugar Crops Research Institute were grown under greenhouse conditions. Actively growing shoots were used as the explants source. The terminal shoots collected from growing plants (2-3 months age) were cut into pieces of 1-1.5 cm long and 0.5 cm wide. 2. The objective of study a. Identifying the best media for induction and regeneration of callus through the tissue culture techniques. b. In vitro evaluation of salt stress effects on callus growth parameters, regeneration and biochemical constituent’s analysis. c. Detection of genetic variability throughout isozymes electrophoresis analysis in inducted callus under salt (NaCl) different concentrations. 3. The most important results could be summarized as follow: a. Effect of explant type and different combinations of growth regulators 1. Callus induction and growth parameter Three media (MSc1, MSc4 and MSc5) out of five tested media produced high callus induction percent (100%) for the three explants (leaf, shoot tip and node). MSc4 gave the highest values of callus fresh weight from leaf (0.633g) , shoot tip (0.549g) and node (0.494g), 57