IMPROVEMENT OF FRUIT SET ON YOUNG PEAR TREES CULTIVAR CONFERENCE WITH GIBBERELLINS

Improvement of fruit set on young Conference pear trees with applications of gibberellins can be considered as a useful way for increasing the early yield productivity or as a phytotechnical measure for repairing frost damage.
The treatment for increasing the early productivity is applied during the full flower period, while the treatments to alleviate frost should be applied within 4 days after frost damage.
Different gibberellins can be applied: GA₃, GA_4/7 or mixtures of gibberellins with a cytokinin, such as GA_4/7 + benzyladenine (Promalin). In this paper the authors discuss the improvement of fruit set on ‘Conference’ from the second to the sixth year after planting.
Every year, the same gibberellin treatments were applied to the same trees during the time of full bloom on the two-year-old wood.
The results indicate that a mixture of a low dose of GA₃ and half a dose of GA_4/7 gave good results for fruit set improvement.
Also, the effect of the gibberellin treatments on flower bud quality and on return bloom are discussed over the whole period.
For GA_4/7, it was possible to compare a standard formulation with 75% GA₄ with a new formulation with 95% GA₄; the standard formulation seems to be better for fruit set improvement but there were no differences in return bloom between the two formulations.
The fruit set effect following a GA₃ treatment was stronger than the effect of a gibberellin treatment with GA_4/7 applied at the same dose rate and at the same time.
The GA₃ treatment was on one occasion more negative in its effects on flower bud formation than the GA_4/7 but on young trees the negative effect of the gibberellin treatments was not always observed.

VIII International Symposium on Pear

T. Deckers, H. Schoofs

fruit set, pear, parthenocarpy, gibberellins

https://doi.org/10.17660/ActaHortic.2002.596.126