ISHS Acta Horticulturae 179: V International Symposium on Growth Regulators in Fruit Production
EFFECT OF SOIL-APPLIED PACLOBUTRAZOL IN DRIP IRRIGATED PEACH ORCHARDS |
| Author: | A. Erez |
| Abstract:
Examination of the paclobutrazol dosage in a conventional "Sunred" nectarine orchard revealed an optimal effect on both vegetative and fruit development at 500 g a.i./ha. A lower dosage had too small an effect, while a higher one retarded growth too severely. The growth inhibiting effect lasted for about 1 year. In meadow-orchard peach trees, a response was detected with 5 mg a.i. of paclobutrazol, but 25 to 50 mg a.i./tree (250–500 g/ha) was needed to obtain the required effect. Fruit weight was increased only slightly by these dosages. Higher paclobutrazol levels resulted in a stronger and longer period of vegetative inhibition. In all cases where inhibition lasted more than a year, a partial recovery was noticed in summer and a renewed inhibition in the following spring. Timing of application was shown to play an important role in the overall vegetative growth of the tree. Autumn or winter applications were very effective compared with spring. Both dosage and timing affect the overall response of the tree. Proper combinations will enable achievement of the required effect. Tetcyclacis, another gibberellin biosynthesis inhibitor, was practically inactive in restricting vegetative growth in the peach. A combination of paclobutrazol and pruning treatments is suggested in order to reduce pruning and increase yield in intensive peach meadow orchards. | |
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