EVALUATION OF FIVE DORMANCY BREAKING AGENTS TO INDUCE SYNCHRONIZED FLOWERING IN 'ROCHA' PEAR
Since hydrogen cyanamide (Dormex) is no longer available to pear growers in Portugal, the few alternatives for dormancy breaking, which are commercially available, mostly nutrients or growth promoters, need to be technically assessed. Five putative dormancy-breaking chemicals were tested for their effect in hastening flowering and synchronizing budbreak in a 19-year-old Rocha pear orchard. Two of them are nitrogen based compounds: (1) Erger®+ActivErger®, and (2) the mixture urea+potassium nitrate and summer oil. The other three are either organic or a mixture of macro- and micro-nutrients and organic compounds: (3) glutathione, an enzyme inhibitor and free radical precursor (Glutabion®), (4) mixtures of polysaccharides and growth regulators (W Uniformity Superplus) and (5) nutrients and N-acetil cysteine, betains and vitamins (Promvit). With the exception of urea+potassium nitrate+oil, a spray adjuvant at 0.05% (Silwet L-77) was added to the mixtures. Depending on the treatment, single or double applications were made between 28 January and 11 February, and bud break started on the 15 March. The first 2 compounds did not effectively release flower buds from endodormancy (similar to controls) but the mixtures with the organic compounds hastened anthesis by 4 days. The differences in phenology were maintained throughout the season but did not have an effect on yield.
Pereira, N., Oliveira, C.M., Mota, M. and Sousa, R.M. (2011). EVALUATION OF FIVE DORMANCY BREAKING AGENTS TO INDUCE SYNCHRONIZED FLOWERING IN 'ROCHA' PEAR. Acta Hortic. 909, 423-428
budbreak, dormancy, growth stimulants, nutrients, Pyrus communis L.