ISHS Acta Horticulturae 160: III International Symposium on Research and Development on Orchard and Plantation Systems
GROWTH CONTROL WITH PACLOBUTRAZOL OF PEACHES GROWN IN A MEADOW ORCHARD SYSTEM |
| Author: | A. Erez |
| Abstract:
Excessive vegetative growth of early ripening peach cultivars was controlled by use of paclobutrazol (pp333) applied as a foliar spray or to the roots under drippers. Strong growth retardation was obtained in the following year from soil application of the chemical in autumn at doses of 1.4 to 4.6 kg a.i./ha. This was accompanied by a marked increase in individual fruit weight. Very little vegetative growth was obtained in the next summer following heading back of the trees at harvest in mid-May. Tree growth was negatively correlated with the dose of paclobutrazol. At doses of 12.5 to 125 mg/plant, in spring application under drippers, the chemical caused growth retardation in 'Earligrande' peaches grown in 50 l containers. The high dose of 125 mg resulted in growth retardation that started 2 weeks after application and lasted throughout the season. Shorter periods of growth retardation were obtained with lower doses, down to only 6 weeks with the 12.5 mg dose. From late April application (about 6 weeks prior to harvest) all levels caused an increase in fruit weight. Foliar spray did not have a consistent effect. Moderate growth retardation was obtained with a midsummer spray of 0.1 or 0.2% a.i. followed by very strong retardation in the following growing season. This retardation effect was much reduced after the trees were headed back at harvest time, in May. On other occasions, very little effect was obtained from foliar spray, probably due to-poor penetration and translocation. All treatments applied in the preceding season that still showed activity during fruit development, led to a marked increased in fruit size and weight. All treatments that were active during the current vegetative development increased flower bud differentiation. | |
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