Control of the vegetative growth of 'Shinseiki' pear trees by prohexadione calcium and root pruning

Bruno Carra,Marcos Antônio Giovanaz,Daniel Spagnol,Carina Pereira Da Silva,José Carlos Fachinello,Mateus Da Silveira Pasa,Everton Sozo De Abreu

doi:10.1590/s0100-204x2017000300005

Abstract

Abstract: The objective of this work was to evaluate the effect of prohexadione calcium (P-Ca) and root pruning (RP) on the control of the vegetative growth and on fruit production and quality of 'Shinseiki' pear trees, under the climatic conditions of Southern Brazil. The experiment was conducted during the 2013/2014 and 2014/2015 crop seasons, in a 15-year-old orchard of 'Shinseiki' pear trees, trained to a central-leader system, with a 2x5 m spacing between plants, grafted onto Pyrus calleryana rootstock. The experiment was carried out in a randomized complete block design, with six treatments and four replicate. The treatments consisted of the control (without P-Ca application or RP), two P-Ca rates (300 and 600 mg L-1), two root pruning intensities (performed on one or on both sides of the tree), and root pruning on one side + 300 mg L-1 P-Ca. P-Ca reduced vegetative growth more effectively than RP, in both crop seasons, and the combination of both techniques did not result in additional control of the vegetative growth, compared with P-Ca alone. Vegetative growth was not affected by increasing the rates of P-Ca. The highest P-Ca dose negativelly affected fruit yield. Regarding fruit quality, RP increases the total soluble solids content at harvest.

Highlights

Vegetative growth control of fruit trees is necessary to avoid excessive shading within the canopy, in order to promote interception of solar radiation and improve fruit quality (Rademacher, 2004)
The use of growth regulators and root pruning (RP) is an alternative to reduce excessive vegetative growth of pear trees [Pyrus pyrifolia (Burm) Nakai], in order to provide an adequate balance between vegetative growth and fruiting
The objective of this work was to evaluate the effect of prohexadione calcium and root pruning on the control of the vegetative growth and on fruit production and quality of 'Shinseiki' pear trees, under climatic conditions of Southern Brazil

Summary

Introduction

Vegetative growth control of fruit trees is necessary to avoid excessive shading within the canopy, in order to promote interception of solar radiation and improve fruit quality (Rademacher, 2004). Excessive vegetative growth negatively affects yield (Pasa et al, 2011) and the control of pests and diseases – due to the reduced efficiency of sanitary applications (Miller & Tworkoski, 2003) –, and increases pruning costs (Hawerroth et al, 2012). The main techniques for controlling vegetative growth in fruit trees are branch bending, pruning, and the use of dwarfing rootstocks. Control of vegetative growth by summer and winter pruning, is essential to ensure the productivity of orchards and to improve fruit quality (Cline et al, 2008). Summer and winter pruning may increase production costs In this context, the use of growth regulators and root pruning (RP) is an alternative to reduce excessive vegetative growth of pear trees [Pyrus pyrifolia (Burm) Nakai], in order to provide an adequate balance between vegetative growth and fruiting

Objectives

Methods

Results

Conclusion