DEPENDENCE OF COLD HARDINESS ON LEVEL OF ENDOGENOUS DORMANCY IN GRAPEVINE BUDS

The study was performed in buds from one-year old canes of Saint Laurent variety during 1993–94, 1994–95 and 1995–96. In every terms of sampling (ones monthly from October to March) the part of buds were treated with calcium cyanamide or garlic juice or with both to break the dormancy and part of buds remained untreated.
After exposition of all buds (treated and untreated) to temperatures near °C for acclimation to frosts the buds were exposed to 4 different frost stresses in controlled conditions.
The level of cold hardiness of buds were determined according the percentage of bursted buds after frost stresses and intensity of dormancy according ,,the mean day of beginning of bursting" of control variants which did not be exposed to frost stresses.
The dependence of cold hardiness of grapevine buds on intensity of dormancy was derived from difference of cold hardiness between cold hardiness of buds with interrupted dormancy and buds with normal dormancy in control variants.
The buds with lowered intensity of dormancy with calcium cyanamide or garlic juice were less hardy to winter frost meanly about 0.4–23.2% in different sampling terms than the buds with normal dormancy.
The results suggested the existence of dependence of cold hardiness on dormancy mainly in the stage of ,,breaking of endogenous dormancy".

V International Symposium on Grapevine Physiology

M. Hubácková

Vitis vinifera, buds, cold hardiness, endogenous dormancy, dependance

https://doi.org/10.17660/ActaHortic.2000.526.38