Carbohydrate content in branches and abscission of fruit of peach trees subjected to chemical thinning

Caroline Farias Barreto,Carlos Roberto Martins,Paulo Mello-Farias,Marcelo Barbosa Malgarim,Roseli De Mello Farias,Renan Ricardo Zandoná,Renata Diane Menegatti

doi:10.1590/s1678-3921.pab2021.v56.02401

Abstract

Abstract The objective of this work was to evaluate the effect of chemical thinning with metamitron on fruit of the Maciel and Sensação peach (Prunus persica) tree cultivars, as well as to identify its relation to the carbohydrate content in their branches. The experimental design was randomized complete blocks, and the treatments were trees with no thinning, manual fruit thinning, and chemical thinning with 200 mg L-1 metamitron applied at 20, 40, and 60 days after full blooming. The evaluated variables were: abscission percentage, yield per plant, number of fruit, presence of lignin in fruit, and carbohydrate content in the branches. The carbohydrate content was evaluated in trees with and without chemical thinning seven days after the application of the product. The use of metamitron promotes fruit thinning in the ‘Maciel’ and ‘Sensação’ peach trees, with a decrease in the carbohydrate content in their branches. Metamitron application 20 and 40 days after full blooming favors fruit abscission in both studied cultivars.

Highlights

Since peach (Prunus spp.) trees exhibit abundant blooming, thinning practices are necessary in orchards to decrease total fruit load and keep energy balance (Farias et al, 2020b)
The use of metamitron as a chemical thinning agent in 'Maciel' and 'Sensação' peach trees had an effect on fruit abscission (Table 1)
In 2015, the decrease in the number of fruit in trees thinned with metamitron was higher than that in trees that were not subjected to any thinning

Summary

Introduction

Since peach (Prunus spp.) trees exhibit abundant blooming, thinning practices are necessary in orchards to decrease total fruit load and keep energy balance (Farias et al, 2020b). These practices result in larger fruits, with an unique flavor and an adequate color throughout commercialization (Farias et al, 2019). Carbohydrates, both stored as starch and produced by photosynthesis, are used for maximum effective fructification (Gonçalves et al, 2016) Their availability is not enough to ensure full fruit growth throughout the cell division process if the fruit load is not adjusted to the volume of the vegetative canopy (Robinson & Lakso, 2011). For peach tree cultivation, studies of the relationship between carbohydrate dynamics and chemical thinning have just started, stimulating the search for knowledge of the effects of the application of certain chemical thinning agents on fruit abscission

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Conclusion