How Grapes in the South Do Not Go Dormant
In the subtropical climate of the southern regions, grape cultivation often faces challenges in dormancy regulation. Abnormalities in the dormant period directly affect the differentiation of floral buds and fruit quality. This article systematically analyzes the grape dormancy mechanism and breaking dormancy techniques, providing cultivators with operable solutions.
Environmental Regulation of Grape Dormancy in the South
Grape dormancy requires the accumulation of about 1000-1500 hours of low temperature at around 7°C, but the southern winter often experiences temperature fluctuations. Through the monitoring of intelligent temperature control systems, when the day-night temperature difference exceeds 5°C, measures must be taken to increase the temperature inside the greenhouse to maintain effective low temperature duration.
Key Points of Physical Breaking Dormancy Implementation
Double-layer film coverage combined with straw insulation, maintaining a greenhouse temperature of 7-8°C during the day and uncovering the covering at night to promote cold storage. Using an intermittent sprinkling system, when the night temperature is below 12°C, automatically spray water every 50 minutes to cool down, continuing for 25-35 days to complete the cold accumulation.
Precise Operation of Chemical Breaking Dormancy
Cyanamide-based breaking dormancy agents need to be applied 30 days before germination, with the concentration controlled at 2.5%-3%. Combined with a 0.3% ammonium nitrate solution can enhance the penetration effect. After application, maintain the humidity inside the greenhouse at over 70% to ensure the full absorption of the agent.
Improvement Plan for Variety Adaptability
Selecting varieties with low cold requirements, such as the Jufeng series, and grafting with the rootstock SO4 can reduce the cold requirement by 30%. Using molecular marker technology to screen for Hd3a dormancy gene variant strains can cultivate new varieties suitable for the south.
By comprehensively applying environmental regulation and biotechnology, establishing a temperature-humidity-light integrated management system can achieve precise control of the grape dormancy period in the south, increasing the uniformity of germination to over 90%, laying the foundation for high yield.