Water scarcity poses a significant threat to kiwifruit production, especially in Mediterranean climates. This study investigated the impact of late-season regulated deficit irrigation (RDI) on water use efficiency and fruit quality of yellow-fleshed kiwifruit (Actinidia chinensis cv. Soreli) over two seasons in central Chile. Four irrigation treatments were applied during fruit ripening: full irrigation (Control), moderate deficits for three or five weeks (D50S and D50L), and complete irrigation suspension for three weeks (D100). While D100 had minimal impact on stomatal conductance, it significantly reduced stem and leaf water potentials, indicating severe water stress. D100 treatment also showed the highest intrinsic water use efficiency (via δ13C enrichment) and improved water productivity by up to 20%. Fruits from D100 and D50S had higher soluble solids (up to 2.0 °Brix) without compromising firmness or yield. Sensory evaluations indicated greater consumer acceptance in water-stressed treatments, especially D100, due to enhanced color and flavor. Principal component analysis confirmed that moderate-to-severe-water stress correlated with favorable sensory profiles. These findings suggest that short-term, late-season water deficits can enhance fruit quality and water use efficiency without reducing yield, offering a sustainable strategy for kiwifruit production under increasing water limitations.

The super high-density (SHD) production system has recently been introduced to the Chilean European plum (Prunus domestica L.) industry, but the potential of applying regulated deficit irrigation (RDI) in this system remains unexplored. As irrigation water availability in Chile has been strongly jeopardized by climate change, there is an urgent need to validate water-conserving practices in modern production systems. A field study was conducted in a commercial SHD European plum orchard (cv. French grafted on Rootpac-20 rootstock) for two consecutive seasons in Peralillo, O’Higgins Region, Chile. The objective of this study was to assess the impact of a late water deficit (LD) on water productivity, fruit quality, plant water relations, and soil microbiota. The results showed that implementing LD enhanced water productivity by 40% without compromising fresh and dry fruit quality. Moderate to severe water stress induced no changes in physiological parameters such as stomatal conductance and photochemical efficiency. Additionally, the LD treatment significantly reduced soil moisture but increased the abundance of certain groups of beneficial soil microbiota and fine roots. These results highlight the potential of LD as a viable water-conserving practice in modern SHD European plum orchards, particularly in regions facing water scarcity due to climate change.

Chile, the leading exporter of cherries (Prunus avium L.) in the southern hemisphere, faces sustained variations in precipitation patterns and high evaporative demand in its productive areas. The low availability of water during the period of highest environmental demand makes it essential to reduce or suspend irrigation applications. In this scenario, regulated deficit irrigation (RDI) after harvest is an efficient strategy for optimizing water use without compromising orchard yields. This study was conducted over three consecutive seasons in a traditional commercial orchard of ‘Santina’ cherry trees grafted onto Colt rootstock, evaluating the effect of two levels of RDI, moderate (MDI) and severe (SDI), on productive and ecophysiological parameters. Both treatments resulted in water savings of between 10% and 28%, without negatively affecting yield or fruit quality. The SDI treatment, despite reaching higher levels of cumulative water stress, improved intrinsic water use efficiency while maintaining stable photosynthetic efficiency. In addition, an increase in the abundance of fine roots and beneficial rhizosphere bacteria populations, such as Azospirillum and Bacillus, was observed, suggesting the activation of water resilience mechanisms mediated by plant–microbiota interaction, possibly associated with stress-induced ecological memory and microbial legacy effects. These results position after-harvest RDI as a sustainable tool for coping with climate variability and water scarcity in commercial cherry orchards.