The Use of Thermotherapy and in vitro Meristem Culture to Produce Virus-Free 'Chancellor' Grapevines.

Grapevines (Vitisspp.) are very susceptible to virus diseases. Virus infection reduces fruit yield and quality. The objective of this work was to determine the usefulness of thermotherapy (37.2°C) and in vitromeristem culture to obtain virus-free grapevine plants cv. 'Chancellor'. Grapevine leafroll-associated virus 1,3(GLRaV-1, 3) infected grapevines were multiplied in vitrofrom two infected mother-plants in half strength Murashige and Skoog medium (1/2MS) supplemented with 0.5 mg/L of BA and the in vitroplants were initially tested by ELISA to confirm their virus status; subsequently, 96 infected in vitroplants were propagated on 1/2MS medium with BA and subjected to 0, 7, 10, 12, 14, 16, 18, 20 or 22 days of exposure at 37.2°C. Afterward, the apical meristems from the plants surviving the thermotherapy treatment were excised and transferred to fresh 1/2MS medium with 0.5 mg/L of BA and grown in a culture room until they developed into entire plants. Control plants and all the plants that survived thermotherapy were assessed for their virus status using both ELISA and RT-PCR. After 20 days of exposure at 37.2°C, 100% of the plants submitted to thermotherapy were found to be virus-free by RT-PCR and ELISA tests. Plants derived from meristems with two or three primordial leaves remained virus infected. However, when meristem culture was combined with thermotherapy (12 or more days of heat treatment), all the meristem-derived plants were virus-free. [ABSTRACT FROM AUTHOR]