On the advancement of bud break and fruit ripening induced by Hydrogen Cyanamide (Dormex®) in sweet cherry: a three-year study

Research to ascertain the effectiveness of hydrogen cyanamide (Dormex®) to advance bloom and fruit ripening of two sweet cherry (Prunus avium L.) cultivars was carried out in the Apulia region (southeastern Italy) during 2002 (964 chill hours), 2003 (592 chill hours) and 2004 (834 chill hours). The effects of four concentrations of hydrogen cyanamide (0.0 as control, 2.0, 3.5 and 5.0%) and three times of application were tested on 'Burlat' and 'Ferrovia'. In 2002, the best results were obtained by early treatments (57 and 50 days before natural bloom of 'Burlat' and 'Ferrovia', respectively) with all concentrations. The maximum advancement of bloom was 11 to 13 days in 'Burlat' and 7 to 9 days in 'Ferrovia'. The maximum advancement of fruit ripening was 7 to 8 days in 'Burlat' and 6 to 8 days in 'Ferrovia'. The unusually mild 2002/2003 winter influenced the research, greatly reducing the advancement of both bloom and ripening of the two cultivars. In 2004, early treatments (79 and 62 days before natural bloom of 'Burlat' and 'Ferrovia', respectively) achieved the best results. The greatest advancement of fruit ripening was by 7 days in 'Burlat' and by 8 days in 'Ferrovia'. In general, early treatments (between 50 and 85 days before natural bloom) and low concentrations (2.0 and 3.5%), applied after a normal winter, were the best in terms of effectiveness, cost and respect of the environment. The effects of hydrogen cyanamide did not extend beyond bud break and climatic factors seemed to influence fruit growth processes from bloom onward, generally decreasing the initial gain in development