European and American grapevines were successfully recovered from GFkV, GLRaV1, GLRaV2, and GLRaV3 viruses by a modified thermotherapy and shoot tip culture.

This study was carried out to determine the effectiveness of modified thermotherapy and shoot tip culture in eliminating grapevines from grapevine fleck virus (GFkV), and grapevine leafroll closterovirus (GLRaV1, GLRaV2, and GLRaV3) all of which are required for certified sapling production. The infected grapevine scions were transferred into 10-liter plastic containers filled with a 1:1 mixture of perlite and peat (v/v), rooted, and saplings were grown. For 40 days, the grapevines were subjected to a modified thermotherapy treatment that included 8 h of darkness at 60–70% relative humidity and 32 °C temperature and 16 h of light (4000–5000 lx) at 60–70% relative humidity and 40 °C temperature. The materials were subjected to shoot tip culture procedures after thermotherapy. All materials were tested again at the end of the acclimatization period. The entire grapevines were virus-free at the end of the process. The survival rates of the grapevines varied. The 41B rootstock had a survival rate of 100%, and the rest had at least one surviving plant out of six. The proposed thermotherapy approach in this study has a high potential for sanitary grapevine sapling propagation when combined with rapid multiplication via in-vitro. [ABSTRACT FROM AUTHOR]