Predawn leaf water potential evolution (Ψ_pd)Vitis vinifera L Viognier/SO₄ (A) and Carignan/R110 (B) during growing season 2017. Each point represents the average of n = 3 plants and bars indicate the minimal significant differences (LSD test, p > 0.05). The grey area indicates the reference values according to a predawn leaf water potential model [32]. Bar graph shows irrigations ( reinforced irrigation, only treatment subplot 2) and rainfall .