Scheduling Regulated Deficit Irrigation with Leaf Water Potential of Cherry Tomato in Greenhouse and its Effect on Fruit Quality  
[PERSON]  
1 Research Group \"Food Quality and Safety\", Centro de Investigacion e Innovacion Agro  
than 60% of the water that is used for irrigation. The world population is increasing more and more. This implies that there is an increase in food consumption, which, consequently, produces a greater consumption of water in agriculture. As a result of this water, resources are being pushed to the limit, causing a serious problem in the world. Thus, [PERSON] et al. argue that there is an urgent need to efficiently use water in agriculture [3]. For this reason, to ensure this essential resource, it will be of great importance to implement strategies that help to optimize the use of water in those irrigated areas. This water sustainability will help to ensure that agricultural activity maintains its development and competitiveness for a long time. A good alternative may be the incorporation of those crops that are more tolerant to drought and the implementation of deficit irrigation (DI) strategies [4]. Deficit irrigation (DI) is a system that is generally applied to create a relationship between the amount of water used for irrigation and the crop optimal performance. This consists of applying water below the plant water requirements, which is marked by evapotranspiration (ETc) [5]. There are many types of DI, of which the most used are: (i) Sustainable Deficit Irrigation (SDI)--continuous reduction of water throughout the cultivation period and (ii) Regulated Deficit Irrigation (RDI)--reduction conducted during a specific period or stage of the crop phenology [2]. This irrigation system can be achieved by providing less than 100% crops evapotranspiration (ETc) either during the growth period (sustained DI) or during the less sensitive phase of the growing cycle [6]. Overall, producing fruits and vegetables using DI will positively contribute to the sustainability of this natural resource. The tomato plant (_Lycopersion esculentum_) is native to Latin America, and more specifically to countries with tropical climates such as Peru and Ecuador. Its name is derived from the Aztec word _xitomate_ or _zitotomate_. At the beginning of the 16 th century, it was brought to Europe, and in the 18 th century to North America, and from there, it spread throughout the world. It belongs to the _Solanaceae_ family and is one of the most widely consumed fruits worldwide [7]. According to the FAO, 2020, in 2016, it exceeded 177 million tons of world production, and in 2018, Spain was the eighth largest producer worldwide, reaching a production of approximately 5,000,000 tons [8]. The importance of water reduction in tomato crop is of high importance as this fruit is the second most consumed vegetable crop worldwide after potato, and because it is a model crop in the research of the physiology of fleshy fruits [9]. Their consumption is mainly based on the tomato sensory properties and on its health-promoting compounds. Tomatoes contain a large content of antioxidant components that can be nutritional (vitamins A, C, and E) and non-nutritional (carotenoids, flavonoids, flavone, total phenolic compounds, etc.) compounds. One of these antioxidants is lycopene, which is a natural carotenoid responsible for providing the red color of tomatoes and helps to prevent cardiovascular diseases and cancer. For this reason, tomato consumption has increased, since consumers are fully aware of these benefits [10]. Similarly, the contents of biochemical compounds are key elements in determining the sensory quality of the fruit, which is determined by its appearance (morphology and color) and flavor, including aroma and taste (volatile compounds, organic acids, and sugars). Two of the quality factors that have the most significance for the food industry and for consumers are sourness and sweetness, which are related to the content mainly of glucose and fructose (sugars) and of citric and malic acid (organic acids).