Fruit thinning of peach trees (Prunus persica(L.) Batsch.): the effect of paclobutrazol on fruit drop and shoot growth

Abstract

SummaryPaclobutrazol (2000 mg l−1) was tested as a fruit thinning agent for cvs Redhaven and Sudanell-1 peach trees. Foliar sprays were applied at three different stages of fruit development: G or petal fall; H or shuck-off; and the beginning of pit-hardening, and compared to trees either hand-thinned or left unthinned. No effect on fruit drop or crop load was observed on Redhaven, but some abscission of fruits occurred on the Sudanell-1 trees treated with paclobutrazol at stages G and H. Shoot growth of both cultivars was inhibited by the two latter applications; this effect was greater in Redhaven, which also showed a reduction in trunk girth increment. In the year after treatments no effect on cropping was observed, but shoot growth was promoted on the trees treated with paclobutrazol in comparison with trees either hand-thinned or left unthinned in the previous year.