Long-Term Correlation between Water Deficit and Quality Markers in HydroSOStainable Almonds

Abstract

Global warming enhances the rainfall and temperature irregularity, producing a collapse in water resources and generating an urgent need for hydro-sustainable thinking in agriculture. The aim of this study was to evaluate the correlation between the water stress of almond trees and quality parameters of fruits, after 3 years of experiments, with the objective of establishing quality markers necessary in the certification process of hydroSOStainable almonds. The results showed positive correlations among the stress integral (SI) and dry weight, color coordinates (L*, a* and b*), minerals (K, Fe, and Zn), organic acids (citric acid), sugars (sucrose, fructose, and total sugars), antioxidant activity, and fatty acids [linoleic acid, polyunsaturated (PUFA)/monounsaturated (MUFA) ratio, PUFA and SFA, among others]. As well as negative correlations of SI with water activity, weight (almond, kernel, and shell), kernel size, minerals (Ca and Mg), fatty acids (oleic acid, oleic/linoleic ratio, MUFA, and PUFA/SFA ratio), and sensory attributes (size, bitterness, astringency, benzaldehyde, and woody). Finally, this research helped to prove key quality parameters that can be used as makers of hydroSOStainable almonds. In addition, it was demonstrated that controlling water stress in almond trees by using deficit irrigation strategies can lead to appropriate yields, improve the product quality, and consequently, lead to a final added value.

Can Sustained Deficit Irrigation Save Water and Meet the Quality Characteristics of Mango?

“…Thus, these results might be used by the farmers and industry when the water availability is below the mango irrigation requirements, producing fruits with a greater quality and Finally, Pearson's correlations were run among the stress integral and all the quality variables with significant differences among treatments. In this sense, a positive relationship among the stress integral with sucrose and total sugars (R = 0.98; p < 0.02; and R = 0.97; p < 0.02, respectively) was shown, implying that deficit irrigation can contribute to sweeter mangoes as previously reported in other crops such as tomatoes, thyme, nectarines or almonds [3,[51][52][53], due to an osmotic adjustment, activated by accumulation of solutes rich in hydroxyl groups (sugars, proline, etc.) in the cytoplasm [54].…”

“…As seen, there are pros and cons of the RDI strategy, because it can either negatively affect the weight or positively affect the fruit quality. In this case, the stress level of RDI must be optimized to assure both parameters as previously observed in other crops [3]. 161a † * and *** significant at p < 0.05 and 0.001, respectively.…”

“…Antioxidant activity and total phenolic content. To measure these parameters, the methodology previously reported in the literature [3,16] was used, with the slight modification that for the extraction step, 5 mL extractant (MeOH/H 2 O 2 (80:20, v/v) + 1% HCl at 20 • C) for 0.5 g of lyophilized mango was used. All measurements were performed in an ultraviolet-visible (UV-vis) spectrophotometer (Helios Gamma model, UVG 1002E; Helios, Cambridge, UK).…”

“…In this regard, there are many deficit irrigation (DI) strategies, among which sustained deficit irrigation (SDI), regulated deficit irrigation (RDI), and partial rootzone drying (PRD) have been successfully used in many crops to improve water use efficiency and fruit quality [2][3][4][5][6]. Sustained deficit irrigation (SDI) is a water optimizing technique which helps in reducing both the biomass production and irrigation water.…”

Scheduling Regulated Deficit Irrigation with Leaf Water Potential of Cherry Tomato in Greenhouse and its Effect on Fruit Quality

“…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].…”