Dormancy breaking and advancement of maturity induced by hydrogen cyanamide: a strategy to improve profits in sweet cherry production

Abstract

Research with hydrogen cyanamide has shown that applications before bud break can be an effective endodormancy-breaking treatment for cherries. An experiment was performed in the Alto Valle of Río Negro, Argentina, on New Star sweet cherry to evaluate the effect of three concentrations of Dormex® (hydrogen cyanamide) on bud break and ripening to obtain economic benefits with first fruit achieving the highest price in overseas markets. Four treatments were performed 30 days before bud break, each treatment covering 6 trees: Dormex® 2% (vol/vol), Dormex® 3%, Dormex® 4% and Control (water). Dormex® treatments were applied with commercial surfactant (2%). Phenology was recorded twice a week, and fruit weight, color, soluble solids and titratable acidity were evaluated during four harvest dates. The optimal maturity for commercial harvest was defined when fruits reached values between 2 to 3 of the color chart (EEA Alto Valle INTA- Área Postcosecha). The cost of Dormex® application was calculated taking into account direct and indirect operating costs. Studies of fresh fruit prices (5 kg boxes) were analyzed for different markets and dates (weeks). Results showed that 4% Dormex® applications advance flowering and fruit maturity approximately 10 and 7 days for New Star . This allowed marketing in weeks 48/49 (instead of week 50 for the control treatment) when fruit prices ranged from 3% to 40% higher depending on the market. We conclude that Dormex® applied to early-ripening cultivars may improve grower profits by reaching markets before prices drop.