Effects of Chilling and Garlic Extract on Bud Dormancy Release in Cabernet Sauvignon Grapevine Cuttings

Abstract

Chemical treatments to break bud dormancy are necessary in vineyards that experience mild winters. Cuttings with a single bud were sprayed with 1.5 or 3.0% garlic extract or 1.5% hydrogen cyanamide. The controls were treated with distilled water. Three lots of canes were submitted to 0, 168, 336, or 508 chilling hr (≤6.0°C), respectively, before spraying. All treatments improved and advanced bud sprouting over the control. The most effective treatment for bud dormancy release was 1.5% H₂CN₂, with up to 80% bud sprouting after 35 days, even for unchilled cuttings. Garlic extract also promoted bud sprouting, attaining greater than 70% budbreak after 35 days for cuttings chilled for 168, 336, and 504 hr. The chilling requirement for Cabernet Sauvignon appears to be close to 336 hr.