PT  - JOURNAL ARTICLE
AU  - Kar, Suraj
AU  - Copp, Cody R.
AU  - DeShields, Joseph B.
AU  - Clark, Ricky W.
AU  - Levin, Alexander D.
TI  - Severe Preveraison and Moderate Postveraison Deficit Irrigation Improves Berry Phenolics in Warm-Climate Pinot noir
AID  - 10.5344/ajev.2025.25016
DP  - 2025 Sep 01
TA  - American Journal of Enology and Viticulture
PG  - 0760024
VI  - 76
IP  - 2
4099  - http://www.ajevonline.org/content/76/2/0760024.short
4100  - http://www.ajevonline.org/content/76/2/0760024.full
SO  - Am J Enol Vitic.2025 Sep 01; 76
AB  - Background and goals Pinot noir is one of the most popular winegrape varieties worldwide, but because of its origins in more cool-climate wine production regions, there is little information regarding its responses to regulated deficit irrigation practices in warm and semiarid climates. Thus, the objective of this study was to observe the responses of Pinot noir production and fruit quality characteristics to preveraison (anthesis to veraison) and postveraison (veraison to harvest) deficit irrigation over two growing seasons.Methods and key findings Treatments consisted of pre- and postveraison irrigation levels at fractions (25, 50, 75, and 100%) of estimated crop evapotranspiration (ETc). Vine water status (stem water potential [Ψstem]) was strongly correlated with applied irrigation during both periods, but particularly during preveraison. Accordingly, berry weight was significantly and linearly reduced with preveraison deficit irrigation, but there was no significant berry weight response to postveraison deficit irrigation. All skin phenolic compound classes—anthocyanins, tannins, and iron-reactive phenolics—showed an inverse linear relationship with preveraison deficit irrigation rate, while these responses to postveraison deficit irrigation were quadratic, both on a concentration and a content basis. With preveraison deficit irrigation, a negative linear relationship was observed between berry phenolics such that the greatest preveraison deficit had the highest total phenolics. In contrast, berry phenolic composition improved with moderate postveraison deficit irrigation and no negative yield effects were observed. The preveraison irrigation rate of 25% of ETc and postveraison rates between 50 to 75% ETc maximized berry phenolics without a significant reduction in vine yield.Conclusions and significance In summary, the results indicate that severe deficit irrigation preveraison, and mild to moderate deficit irrigation postveraison, improve berry phenolics in warm-climate Pinot noir.