IN VITRO SELECTION OF HYP TOLERANT CELL LINES FROM 'CHARDONNAY' EMBRYOGENIC SUSPENSION CULTURE

Breeding for cold and salt tolerance of woody plants such as grapevine by classical methods is time consuming. An alternative approach to improve these traits is to induce and select somaclonal variation using an in vitro culture strategy. Suspension cultures of ?Chardonnay? Proembryogenic Masses (PEMs) were radiated with 10, 40, 60, 100, 500 Gy of Co60 and then transferred to the selection medium (Murashige and Skoog medium plus 0.5 µM 2, 4- Dichlorophenoxyacetic acid and 10 mM hydroxyproline). The hydroxyproline resistant cell lines were obtained from each dose of Co60 treatment (10, 40, 60, 100 Gy) except the 500 Gy, but most became brown after subculture. However, a stable cell line derived from radiation of Co60 at the 100 Gy dose was obtained, which was subsequently confirmed by a test for hydroxyproline resistance and measurement of proline content. After 4-week exposure to different concentrations of hydroxyproline, the resistant cell line eventually grew well on MS medium plus 0.5 µM 2,4-D and 4.0 mM hydroxyproline, while the control line turned brown and eventually died. The resistant PEM also had higher free proline content than the control after treatment with hydroxyproline. The ?resistant? PEM line of ?Chardonnay? germinated, and the plantlets are being used for further evaluation for salt, drought and cold tolerance.