Pre-harvest regulated deficit irrigation management effects on post-harvest quality and condition of V. corymbosum fruits cv. Brigitta

- Post-harvest fruit condition does not seem to be affected by water treatments.
- Mild deficit treatment can achieve equivalent fruit quality as control plants.
- Mild deficit treatment can produce similar antioxidant capacity as control fruits.
- Severe water deficit enhances oxidative damage and lowers antioxidant capacity.

Blueberries are highly sensitive to water stress, especially during fruit development when fruit yields and post-harvest quality can be affected. Regulated deficit irrigation (RDI) can increase fruit quality of many fruit crops without reducing yield. However, the influence of pre-harvest RDI on postharvest quality of blueberry has not been studied. Our aim was to evaluate the post-harvest quality of V. corymbosum fruits cv. Brigitta grown under pre-harvest RDI. Two locations were used for this research: (1) Colbún, Maule Region, Chile (35° 41′ 12.99″ LS; 71° 25′ 8.75″ LW) during the 2013-14 and 2014-15 seasons using six-year-old plants, and (2) South Haven, Michigan, USA (42° 21′ 16.26″ LN; 86° 12′ 48.88″ LW), during the 2014 season, on twenty-six-year-old bushes. Plants were subjected to three irrigation treatments that replaced 50, 75 or 100% (control) of actual evapotranspiration (ETa). Fruits were harvested at >90 full color and stored for 30 and 60d at 0-2 °C + 3d at 18-20 °C. Water treatments had no effect on the proportion of sound, dehydrated or decayed berries after storage. However, fruit quality was affected, with mild water deficit (75% ETa) producing similar fruit quality, i.e., firmness, titratable acidity, soluble solids and antioxidant activity as fully irrigated plants (100% ETa), and lower oxidative stress than 50% ETa treatment at 60 + 3d, but with lesser weight loss. Blueberries are considerably sensitive to water stress, with 50% treatment showing the highest lipid peroxidation and lowest antioxidant activity (ORAC) for both 30 + 3d and 60 + 3d, as well as by decreasing fruit quality (high SS and low TA). We have shown that applying 25% less water to highbush blueberries does not reduce fruit quality or levels of antioxidants.