Effect of Hydrogen Cyanamide on Bud Break, Fruit Yield and Quality of Highbush Blueberry in Greenhouse Production

Highbush blueberries need sufficient chilling exposure to induce bud break and flowering, which limits their cultivation in warm areas as well the profitability of protected greenhouses. Hydrogen cyanamide (H2CN2, HC), gibberellic acid (GA3), ethephon (CE), mineral oil (MO), potassium nitrate (KNO3) are often applied deciduous fruit trees advance set. In this study, experiments were conducted northeast China determine effects different concentrations HC or combination with GA3, CE, MO, KNO3 on break, quality, yield greenhouse-grown highbush blueberry (Vaccinium corymbosum L.). The results showed that all treatment agents could by at least 15 days ripening 16 compared control. addition, treatments promote development flowers fruits shorten flowering harvest periods. Compared control, 0.5% 0.67% increased 5-year-old 7-year-old bushes, especially early yield. Experiments carried out over two consecutive years varieties, namely ‘M7’ ‘Brigitta’, further confirmed positive effect application also had no negative quality. These findings may encourage growers consider spraying greenhouses increase yield, order schedule time for a more lucrative marketing period.