GIBBERELLIC ACID REDUCES FLOWERING AND TIME OF MANUAL THINNING IN ‘MACIEL’ PEACH TREES

Marcos Antônio Giovanaz,José Carlos Fachinello,Diego Weber,Bruno Carra,Daniel Spagnol

doi:10.1590/0100-29452016692

Marcos Antônio Giovanaz, José Carlos Fachinello + Show 3 more

Open Access

https://doi.org/10.1590/0100-29452016692

Copy DOI

Abstract

ABSTRACT The thinning peach fruits is to reduce the load of the plant with the aim to improve the size, flavor and color of the remaining fruits. However, the practice of thinning requires high demand of manpower and become more expensive the production costs. The objective of this study was to evaluate the reduction of flowering buds and the time of hand thinning in ‘Maciel’ peach after gibberellic acid (GA3) application at different times and concentrations. The experiments were performed in the harvests of 2012 and 2013 in a commercial peach orchard located in the county of Morro Redondo, RS. The plants of cultivar Maciel, in 2012, were sprayed with four doses of GA3 0, 25, 75 and 125 mg L-1, at different times 20, 40 and 60 days after full bloom (DAFB). The number of flowering buds and consequently thenumber of flowers was reduced in the 2013 season after application of GA3 on the 2012 harvest. The manual thinning decreased with doses applied at 60 DAFB. The number of flowering buds and consequently the number of flowers was reduced in 2013. There was reduction of manual thinning when applied at 60 DAFB. The doses of 25, 75 and 125 mg L-1 applied at 60 DAFB resulted in a reduction of 50.1, 76.9 and 87.1%, respectively, at the time of hand thinning. When applied the dose of 25 mg L-1 of GA at 60 DAFB reduces the number of flowering buds and hand thinning time in the next cycle in ‘Maciel’ peach, without compromising production.

Highlights

The large amount of flowers and the high effective peach fruit set (NAVA et al, 2009) result in a load that the plant cannot stand, bearing fruit with low commercial value
In the peach tree, thinning is usually performed in a manual way and is a delicate operation that requires high demand of manpower, short period for realization and high cost (COSTA; VIZZOTTO, 2000)
A strategy that can be used to help the realization of thinning is the application of gibberellins in the flowering induction period, since it reduces the number of flowering buds of the subsequent cycle on stone fruit trees (SOUTHWICK; GLOZER, 2000; GRENNE; COSTA, 2013)

Summary

Introduction

The large amount of flowers and the high effective peach fruit set (NAVA et al, 2009) result in a load that the plant cannot stand, bearing fruit with low commercial value. In this regard, the thinning of fruit or flowers aims to reduce the plant load, increasing the size and quality of fruits, avoiding the production alternation and maximizing the final value of the product (BYERS et al, 2003; MEITEI et al, 2013). The results in reducing the number of flowers by applying gibberellins have been demonstrated for many years (HULL; LEWIS, 1959), and the exogenous application of gibberellic acid (GA3) continues to be studied in recent decades, in peach trees, nectarine and plum trees (SOUTHWICK et al, 1995; GARCÍA-PALLAS et al, 2001; STERN; BEN-AIRE, 2009)

Objectives

Methods

Results

Conclusion