EFFECTS OF SOME GROWTH REGULATORS ON BRANCHING AND FLOWERING OF YOUNG APPLE TREES

L.J. Edgerton
The early development of lateral shoots and spurs on young apple trees is essential for early productivity. Several plant growth regulators including 6-benzlaminopurine (BA), gibberellins A4+A7 (GA4+A7), 2-chloroethylphosphonic acid (ethephon) and succinic acid-2–2-dimethyhydrazide (daminozide) have been used in studies on branching, canopy development and flowering to facilitate this objective on several apple cultivars.

An application of BA and GA7+A7 at 250 to 500 ppm on apple seedlings or nursery trees when the shoots are 20 to 40 cm tall increases the number of laterals that form, and generally the length and quality of the laterals. If a buffering agent and adjuvant such as 'Buffer X' was used with the BA its performance was generally equal to or superior to that of a BA+GA4+A7 formulated combination.

If the timing was delayed, or the concentration of the BA was too low to induce the lateral buds to break into shoots, the buds in the treated area often enlarged in size. These buds have produced superior lateral shoots during the first year in the orchard as compared to the performance of lateral buds in the same location on nontreated nursery trees.

The application of BA or the BA+GA4+A7 formulation has also been beneficial in promoting a more desirable branching and canopy development in young spur type 'Delicious' and 'McIntosh' cultivars.

Edgerton, L.J. (1983). EFFECTS OF SOME GROWTH REGULATORS ON BRANCHING AND FLOWERING OF YOUNG APPLE TREES. Acta Hortic. 137, 77-82
DOI: 10.17660/ActaHortic.1983.137.6
https://doi.org/10.17660/ActaHortic.1983.137.6

Acta Horticulturae