Study of the Impact of Different Irrigation Regimes on the Quality Attributes and Phenolic Compounds Profile of Selected Goji Berry Varieties (Lycium barbarum L.) Cultivated Under an Organic Cultivation System in Southwestern Spain

Abstract

In a context of increasing water scarcity in southern Spain, improving water-use efficiency has become essential for sustainable crop production. This study evaluated the effects of two irrigation regimes (100% and 75% of crop evapotranspiration, ETc) on the quality attributes and phenolic compound profile of three goji berry varieties (NQ1, Sweet Lifeberry, and Turgidus) cultivated under organic conditions in southwestern Spain. Key quality parameters including color, sugars, acidity, firmness, moisture, size, and weight were evaluated together with phenolic compounds profiling using UHPLC-MS/MS and antioxidant activity assays. The goji berry varieties studied showed significant differences (p < 0.05) in most of the variables analyzed, confirming the dominant influence of genotype. In contrast, no significant differences were detected in most quality attributes between berries cultivated under full irrigation (100% ETc) and deficit irrigation (75% ETc). However, deficit irrigation promoted the accumulation of hydroxycinnamic and hydroxybenzoic acids, while flavonols and flavan-3-ols showed a decreasing tendency. Despite these compositional shifts, antioxidant capacity was generally higher under full irrigation. Among the varieties, NQ1 berries exhibited the highest total phenolic content and antioxidant activity. Harvesting time further influenced phenolic distribution and antioxidant behavior. These findings suggest that moderate deficit irrigation can be applied as a sustainable water-saving strategy for goji berry cultivation under Mediterranean conditions without compromising fruit quality.