ISHS Acta Horticulturae 441: V Temperate Zone Fruit in the Tropics and Subtropics
EFFECT OF HYDROGEN CYANAMIDE TREATMENT AFTER VARIOUS PERIODS OF CHILLING ON BREAKING ENDODORMANCY IN APPLE BUDS |
| Author: | G.A. Finetto |
| Abstract:
The timing of hydrogen cyanamide (H2CN2) application for breaking dormancy affects the response of temperate fruit species. This is important in areas where winter temperatures are variable, but few data are available as to response. The aim of this study was to investigate the relationship between chemical concentration and chilling accumulation in breaking dormancy in some mid- and high-chilling apple cultivars. During two years hydrogen cyanaide was tested at three concentrations (0.5, 1 and 2%) in the Po Valley. Every week during the winter season one-year-old shoots and spurs from four apples cultivars were collected and treated ; the bases were placed in water and the shoots were put in a growth chamber for 20 days at 21°C. The degree of bud burst was expressed as percentage of buds opened and as bud development stage. The response to H2CN2 varied with chilling received, GDH accumulated and the chilling requirement of the cultivars. The highest concentration gave the best results at minimal chilling accumulation in all the cultivars. The results indicated that H2CN2 breaks endodormancy easily in cultivars with lower chilling requirements, the effect of the compound increases with the chilling accumulation, and, finally, within cultivars the two types of buds differ in response. | |
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