Regulated deficit irrigation effects on physiological parameters, yield, fruit quality and antioxidants of Vaccinium corymbosum plants cv. Brigitta

Abstract

Highbush blueberries require sufficient water throughout the growing season, especially during fruit development. Regulated deficit irrigation (RDI) has been used in many fruit crops to save water and potentially increase fruit quality without reducing yield. Our aim was to determine the effects of RDI on yield, plant–water relations, and fruit quality at harvest. Three irrigation treatments based on actual evapotranspiration (ETa) were applied: 50, 75 and 100% (control) to six-year-old ‘Brigitta’ highbush blueberries in Colbun, Maule Region, Chile, for seasons 2013–2014 and 2014–2015 and to 26-year-old ‘Brigitta’ plants in South Haven, Michigan, USA, during the 2014 season. Severe water deficit treatment (50% ETa) decreased photosynthetic rate, vegetative growth (second season in Colbun and South Haven’s trial), and fruit quality (berry size, titratable acidity, soluble solids, weight), and increased oxidative stress during both seasons in Colbun. The 50% ETa treatment also had the highest yield reduction during Colbun’s second season. In contrast, mild water stress (75% ETa) resulted in similar fruit yields and quality (firmness, fruit size, titratable acidity, soluble solids and berry weight) but with higher water productivity than the 100% ETa treatment, while it achieved intermediate values for antioxidant capacity compared to the 50% ETa treatment.