Effects of pruning and season on antioxidant and quality traits of blueberries

Abstract

Consumer interest in natural antioxidants has risen because their intake is linked to the prevention of chronic diseases. Blueberries (Vaccinium spp.)—rich in flavonoids, vitamin C and other bioactive compounds—are therefore being cultivated beyond temperate regions. In tropical areas, however, the lack of chilling hours may alter fruit physiology, and little is known about how pruning practices modulate quality under these conditions. The objective of this study was to quantify the effects of pruning types and seasons on the antioxidant activity, physical and chemical characteristics (TSS, TTA, TSS/TTA), and ash, moisture, and fiber contents in blueberries of the cultivar Biloxi grown under tropical climate conditions (without chilling hours), in Brasilia, DF, Brazil. The trial followed a randomized-block design with three replications. Plants received either severe pruning removing lateral branches (SPRLB) or severe pruning maintaining lateral branches (SPMLB) in winter, spring, summer or autumn; fruit harvested over the subsequent four weeks was analysed for DPPH radical-scavenging capacity, total soluble solids (TSS), titratable acidity (TTA), TSS/TTA ratio, ash, moisture and fibre contents. Pruning season exerted the strongest effect. Autumn pruning—regardless of type—produced the highest antioxidant activity and elevated TSS. SPRLB increased TTA, whereas SPMLB enhanced the TSS/TTA ratio during warmer seasons. These findings demonstrate that pruning season plays a key role in enhancing blueberry fruit quality under tropical conditions.