ISHS Acta Horticulturae 80: Symposium on Growth Regulators in Fruit Production
CHEMICAL CONTROL OF FRUIT SET AND JUNE DROP IN YOUNG GOLDEN DELICIOUS APPLE TREES |
| Authors: | G. Cristoferi, N. Filiti, S. Sansavini |
| Abstract:
Young "Golden Delicious"/seedling apple trees were sprayed with "PP 528" (ethyl-5(4-chlorophenyl)-2H-tetrazol-2-ylacetate) for 2 seasons in succession when shoots were 15 – 20 cm in length. The treatment resulted in: (a) reduced shoot growth; (b) reduced cross-sectional area of the trunk and (c) increased n° of feathers formation. Half of the treated and control trees were pruned prior to full bloom in the 3rd season. Results revealed that "PP 528" increased the percentage of fruitful buds but not fruit set. The latter was increased by pruning alone. Analyses of the shoot apices 5 days after the initial treatment with "PP 528" revealed a reduction in levels of auxin-like substances and acid and neutral gibberellin-like substances. | |
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