The possibility for obtaining virus free plants from Impatiens hawkerii
Bull. shoots infected with Tomato spotted wilt virus (TSWV) through meristem-tip culture was examined. TSWV presence in I. hawkerii
plants was detected by DAS-ELISA and RT-PCR and identification of the virus was confirmed by sequencing one of the chosen isolate (GenBank Accesion CQ132190). Meristem-tip explants (0.3-1.5 mm) from virus-infected shoots are cultured on MS media supplemented with different concentrations of the cytokinins, CPPU or TDZ (0.01-1.0 µM), respectively. Using this system, a large number of in vitro
shoots could be produced from a single explant. Also, cytokinins showed a stimulatory effect on the length, fresh and dry weights of the newly formed shoots. Plant pigments content in I. hawkerii
shoots increased significantly in the presence of cytokinins. Rooting of shoots was spontaneous on the same media. Rooted plantlets were transferred to soil where 97% successfully acclimatized. By DAS-ELISA and RT-PCR, 80% of the in vitro
plantlets were shown to be a virus-free. Considering these, the present protocol seems to be an efficient method for in vitro
generation of virus-free I. hawkerii
plantlets by meristem tip cultures.