THE POSSIBLE ´MODE OF ACTION´ OF THINNING BIOREGULATORS AND ITS POSSIBLE CONTRIBUTION TO THE UNDERSTANDING OF ´THINNING VARIABILITY´ IN APPLES

Abscission of young fruit is a correlative, inter organ effect and, therefore, under the control of a considerable number of other ‘tree factors’, such as vegetative growth rate, as well as environmental effects. Since chemical thinning is considered as an enhancement of the natural abscission process, it seems reasonable that part of the great variability generally observed with chemical thinning can be attributed to similar correlative effects. The purpose of this presentation is to address this question.