ISHS Acta Horticulturae 395: Dormancy and the related Problems of Deciduous Fruit Trees
MEANS TO COMPENSATE FOR INSUFFICIENT CHILLING TO IMPROVE BLOOM AND LEAFING |
| Author: | A. Erez |
| Keywords: | Dormancy, rest breaking chemicals, evaporative cooling, Dynamic model |
| Abstract:
Physical means: Excessively high daytime temperature is the main cause, under subtropical climate, for poor budbreak. Whenever night temperatures reach 12°C or lower, chilling will accumulate if day temperatures is kept below 19°C. This can be achieved in warmer locations by using over the tree micro-sprinklers to cool the buds by evaporative cooling during daytime. Duration of operation of this system depends on the climatic conditions as determined by the dynamic model. Apart from low chilling cultivars, management practices are important for lowering the chilling requirements of buds. These includes especially controlling tree vigor, training to a horizontal tree form, preventing late vegetative growth and delaying winter pruning. Chemical means: DNOC, a component of the main rest breaking agent for many years was banned recently causing a concern for an appropriate substitute. Oil-cyanamide is an effective replacement in apples. For stone fruits, combinations of oil, KNO3 and gibberellic acid with a new penetrator - Armobreak - may open new possibilities. | |
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