Effects of Temperature Fluctuations on Cabernet Sauvignon Branches and Wine Grape Appellation Yields: An Analysis Based on the Standardized Temperature Adaptation Index

Climate fluctuations due to global warming significantly impact the wine grape industry. This study introduces the Standardized Temperature Adaptation Index (STAI), which is specifically designed to isolate temperature trends and quantify the effects of temperature fluctuations on low-temperature stress affecting Cabernet Sauvignon branches and yields in the wine grape production regions of Xinjiang. A low-temperature fluctuation experiment was conducted on Cabernet Sauvignon branches to simulate the temperature conditions and fluctuations experienced by wine grapes during the overwintering period. The treated branches then underwent recovery growth experiments, during which key physiological stress parameters were measured to assess the impact of temperature fluctuations on grape growth and development during overwintering. The results indicated that under identical low-temperature conditions, increased temperature fluctuations led to a 62% reduction in the budding rate of Cabernet Sauvignon branches, a 6% increase in relative conductivity, and elevated levels of proline, malondialdehyde, and soluble proteins. Additionally, the activities of superoxide dismutase, peroxidase, and catalase initially rose and then declined, indicating that temperature fluctuations intensified low-temperature stress. Data analysis from four wine grape production regions in Xinjiang between 2000 and 2020 revealed that temperature fluctuations corresponded with the peaks and troughs of yield fitting curves, demonstrating a negative correlation. As temperature fluctuations increased, yields decreased. The STAI introduced in this study is a straightforward, standardized measure that accurately reflects the effects of temperature fluctuations on grapes and is a valuable tool for future research on temperature variability and its impacts.