Abstract

Labour is becoming scarce in many blueberry-growing regions, with pruning requiring the most labor, besides harvest. A new approach called sectorial pruning (SP), in which each winter all canes are removed at the base in one quarter of the plant was trialed for three years in 12-year-old 'Brigitta' plants growing in a commercial field in Linares, Chile (35°51'S, 71°36'W). SP was compared with quick pruning (QP) in which the oldest cane of each quarter was removed from the plant each year. SP and QP removed 31 and 18% of the total basal area of the plant, respectively. SP had higher yields only in year 1 (8.0 vs. 5.5 kg plant-1). Pruning treatments had no effect on fruit number, but fruit weight was greater for SP in the first two years. Regarding fruit quality, fruit diameter was increased by SP only in year 1 (14.2 vs. 13.3 mm); while QP had higher fruit firmness only in year 2 (153.6 vs. 122.1 g mm-1). Considering the overall effects of the three seasons, pruning had no significant cumulative effects on yield and its components (fruit weight and number) or quality (fruit diameter and firmness). SP had in average 32% higher yields and its fruits were 19% heavier than QP. The most marked effects of SP on yield and fruit weight were detected in the first two seasons (32-45% greater than QP). The effects on fruit number, firmness and fruit diameter were milder and unstable. The reduction in yield with SP after the second season would be due to a greater proportion of older and highly productive canes being removed and replaced by younger unproductive canes. Delaying the removal of the second and third quarters in SP might prove adequate to sustain high yields, while reducing the need for labor.