Blueberry require chilling hours accumulation in the fall/winter. Insufficient cold accumulation can cause deficient and desuniform sprouting and blooming, with negative consequences on yield. The research conducted in Passo Fundo University, state of Rio Grande do Sul, had the objective of studying the dormancy breaking of blueberries cultivars (Georgiagem, Climax and Aliceblue) under greenhouse conditions, submitted to treatments with hydrogen cyanamide (HC) at the doses of 0.52% and 1.04% (1% and 2% of the commercial product Dormex®), with the addition of 0.5% of mineral oil (MO), and compare them to a control, without hydrogen cyanamide treatment. Planting was made in December 2005, at a 0.7 m x 2.0 m space, with drip irrigation. The plants were evaluated in the third vegetative cycle and first production. The results showed that chemical induction of dormancy breaking at the end of July shortened and standardized flowering, and in the cultivars Georgiagem and Climax anticipated bud break. The use of HC at the concentrations of 0.52% and 1.04%, in combination with 0.5% of MO, did not affect the sprouting percentage, but reduced the yield, mainly the highest concentration, with evidence of phytotoxic effects.
Vaccinium sp.; sprouting; blooming; fruit production
