Micropropagation and Assessment of Genetic Stability of Acclimatized Streptocarpus x hybridus Voss Plantlets Using RAPD Markers

A micropropagation protocol via direct shoot organogenesis from Streptocarpus x hybridus Voss. leaf explants was established in this study. The shoot induction of three Streptocarpus cultivars (‘Snow White’, ‘Black Panther’ and ‘Slumber Song’) was successfully achieved on Murashige and Skoog (MS) medium supplemented with 0.2 mg L-1 -indole-3-acetic acid (IAA) and 0.2 mg L-1 thidiazuron (TDZ). In proliferation stage, the effects of two combinations of plant growth regulators -PGR- (V1-0.2 mg/L-1 IAA + 0.5 mg/L-1 BAP and V2-1.0 mg L-1 NAA + 0.2 mg L-1 TDZ) on shoot number and length were examined. The results suggest that PGRs combinations significantly influenced shoot proliferation and root induction in all Streptocarpus cultivars. Among the treatments, 0.2 mg L-1 (IAA) in combination with 0.5 mg L-1 6-benzylaminopurine (BAP) were the most effective for in vitro shoot multiplication and rooting. The in vitro rooting percentage was also determined before subjecting the plantlets to the acclimatization process. Due to acclimatization, Streptocarpus plantlets showed a very high rate of survival (90%). The generated PCR-RAPD profiles for the selected in vitro-raised plants and donor plants were similar which indicates the clonal or true-to-type nature of the progenies.