Vertical cordon as a climate-adaptive viticultural practice: improving water productivity and oenological potential in the low-yielding minority cultivar Maturana Blanca

Water scarcity and rising temperatures increasingly threaten Mediterranean viticulture, demanding strategies that improve productivity, water efficiency, and must quality. Over three consecutive growing seasons (2021–2023), we used a 2 × 2 factorial design to evaluate two training systems (head-trained (HT) and vertical cordon (VC)) and two irrigation regimes (non-irrigated (NI) and supplementary irrigation at 30% of daily water deficit (SI)). We assessed vine physiology, vegetative growth, yield components, water productivity (WP), and must composition in the minority cultivar Vitis vinifera L. cv. Maturana Blanca under semi-arid Mediterranean conditions. Irrigation was the primary driver affecting vine water status and leaf gas exchange, with the variety exhibiting near-anisohydric behavior, with non-irrigated vines reaching midday leaf water potential values as low as −2.10 MPa at ripening in 2022. Vegetative growth was primarily determined by the training system, with VC vines developing 31.4% greater leaf area through a greater number of shorter and thinner shoots, without increasing pruning weight. Yield was 81.4% higher under VC system, mainly due to a 92% increase in clusters per vine associated with the greater bud load retained in this system. The SI treatment increased yield by 32.3% but resulted in a 21.4% reduction in WP. Conversely, the VC system nearly doubled WP relative to HT under identical water inputs. In the three-year analysis, both VC and SI significantly reduced total soluble solids, with VC decreasing alcohol content by 0.63% v·v ‐1 relative to HT, while SI reduced it by 0.43% v·v ‐1 . The VC system also produced musts with lower pH and higher titratable acidity, which are attributes of considerable interest under climate-warming scenarios. These results demonstrate that vertical cordon training combined with regulated supplementary irrigation represents an effective and independently applicable strategy for enhancing productivity, optimizing water use, and improving must quality in minority white grape cultivars under water-limited Mediterranean conditions.