Abstract: Clarifying the impacts of leaf picking in different periods on the microclimate around grape clusters and the berry quality components can provide a basis for refining vineyard management practices and producing high-quality wine grapes. An experiment was conducted in the eastern foothills of the Helan Mountains using Vitis vinifera “Cabernet Sauvignon”, a major wine grape variety. Leaf picking was performed at two post-veraison stages: the third week (T3) and the fifth week (T5) after veraison. At each stage, there were three treatments: removal of leaves on the east side of the canopy (E), on the west side (W), or on both sides (EW). The results showed that: (1) From veraison to maturity, air temperature around grape clusters and berry temperature showed a fluctuating decline. Leaf removal generally increased cluster-zone air temperature, berry temperature, and the level of photosynthetically active radiation (PAR) measured linearly across clusters. Compared to the control (CK), the accumulated temperature around grape clusters and on berry across different treatments increased by 19.9-29.9 ℃·d and 43.1-54.7 ℃·d on average and linear PAR by an average of 1689.3 μmol·m^-2·s^-1. (2) Leaf picking significantly increased the content of soluble solids, reducing sugars, and pH, thereby accelerating sugar accumulation. It significantly decreased titratable acidity, but promoted the decomposition of malic acid and tartaric acid, increased the citric acid content, and enhanced the accumulation of total phenols and anthocyanins. The effects on sugar and acid metabolism were more pronounced when leaf picking was performed at T3 compared to T5. (3) A comprehensive evaluation using the TOPSIS model based on the entropy weight method scored the highest under the east-side leaf picking treatment at T3, indicating the highest fruit quality. (4) For north-south oriented vineyards in the eastern foothills of Helan Mountains, a canopy management strategy involving east-side leaf picking in the third week after veraison is recommended. This approach effectively regulates key quality components, helps reduce disease incidence, and improves final grape quality.

Key words: leaf picking period, TOPSIS model, quality evaluation, the wine-producing area on the eastern foothills of the Helan Mountains, microclimate