Abstract: An experiment was conducted from 1 November 1998 to 15 March 1999 and 1 November 1999 to 15 March 2000 to study the role of hydroperoxidase enzymes (peroxidase and catalase), phenols and their relationship with the intensity of dormancy in grape cv. Pusa Seedless, grown under the subtropical conditions of north India. Catalase activity increased during the early part of the dormancy cycle then declined and was lowest at bud break. On the other hand, peroxidase activity was lowest at the initial stages of dormancy then increased and was maximum at dormancy breaking. Phenol content increased from the onset of dormancy to deep dormancy then declined and was lowest at sprouting.
