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The tomato cultivated surface is one of the most important surfaces in the world. This crop needs a sufficient and continuous supply of water during vegetative growth. Therefore, production may be at risk in warm and water-scarce areas. Therefore, the implementation of irrigation alternatives such as regulated deficit irrigation (RDI) is of great importance to reduce the use of water and improve the production of the quality of tomatoes. The objective of this work was to evaluate the deficit irrigation scheduling using plant water status as a tool in deficit irrigation. Experimental design was a randomized design with four replications per treatment. Two irrigation treatments were applied: Control (125% of crop evapotranspiration (ETc)) and Regulated Deficit Irrigation (RDI). This latter treatment considered different threshold values of midday leaf water depending on crop phenological stage. No differences were observed in yield, with RDI treatment being more efficient in the use of irrigation water than the control. Besides, RDI tomatoes presented, in general, greater weight, size, Total soluble solids (TSS), sugars, antioxidant activity, lycopene, β-Carotene, and redder color with more intense tomatoes flavor. Finally, it might be said that RDI strategy helped to reduce 53% of irrigation water and to improve the nutritional, functional, and sensory quality of tomatoes.

Olive trees are extremely drought-resistant species. This particularity could be used to reduce water needs in regulated deficit irrigation scheduling. However, the yield response to water deficit is linked to the moment and the level of water stress imposed. Pit hardening has been commonly used as the stage to decrease irrigation, but it is not measured under field conditions. The aim of this work is to describe the impact of water stress conditions on yield response for table olive trees, considering an accurate determination of the endocarp development. The experiment was performed from the 2020 to the 2023 seasons on a two-year-old super-high density table olive orchard (cv Manzanilla de Sevilla). The three irrigation treatments (six repetitions) were: Control, no water stress conditions throughout the season in 2020 and 2021, and mild water stress to reduce vigour in 2022 and 2023; Regulated deficit irrigation (RDI), based on a moderate to severe water stress during pit hardening, using midday stem water potential measurements; and Rainfed. Endocarp development was established using the pit-breaking pressure throughout the 2021, 2022 and 2023 seasons. Water relations, vegetative growth, number of inflorescence and fruits, yield and fruit quality were measured during the experiment. Crown volume limited yield in Rainfed treatments but not in RDI, compared to Control. The number of inflorescences and inflorescence set was not affected in RDI and Rainfed, only reduced in severe water stress in 2023. RDI presented a similar yield response to Control, with a reduction of 50 % on applied water and a significant more negative midday stem water potential. The Rainfed trees were unsuitable for table production because rehydration did not recover fruit size enough to be commercial. Endocarp maintained the capacity of growing until the end of the season.

The scarcity of water resources affects tomato production. Deficit irrigation may optimize water management with only a low reduction in yield. Deficit irrigation scheduling based on applied water presented no clear conclusions. Water stress management based on plant water status, such as water potential, could improve the scheduling. The aim of this work was to evaluate the physiological and yield responses of different tomato cultivars to deficit irrigation. Three experiments were carried out in 2020 and 2022 at the University of Seville (Spain). “Cherry” and “chocolate Marmande” cultivars with an indeterminate growth pattern were grown in a greenhouse. Treatments were: Control (full irrigated) and Deficit. Deficit plants were irrigated based on water potential measurements. Moderate water stress did not significantly reduce the yield, although it affected other processes. Fruit size and total soluble solids were the most sensitive parameters to water stress. The latter increased only when persistent water stress was applied. However, truss development and fruit number were not affected by the level of water stress imposed. Such results suggest that moderate water stress, even in sensitive phenological stages such as flowering, would not reduce yield. Deficit irrigation scheduling based on plant water status will allow accurate management of water stress.