The effects of aminoethoxyvinylglycine and foliar zinc treatments on pre-harvest drops and fruit quality attributes of Jersey Mac apples

The present study was carried out to investigate the effects of pre-harvest aminoethoxyvinylglycine (AVG, 250 mgL(-1)) and zinc (0,3% ZnSO4) treatments on pre-harvest fruit drops, internal ethylene concentration (IEC), fruit weight, color characteristics, fruit firmness, soluble solids content (SSC), titratable acidity like quality attributes and antioxidant activity, total phenolics, micro and macro elements of Jersey Mac apples (Malus x domestica). Compared to control treatment, except for 22 July, pre-harvest drops were significantly reduced with all treatments in all measurement times. Zn +AVG treatment was found to be more effective in reducing pre-harvest fruit drops. IEC decreased with AVG, Zn and Zn +AVG treatments. Single AVG treatment was more effective on IEC decreases. While flesh softening was retarded with AVG treatments, Zn treatments stimulated flesh softening. Fruit weights increased with Zn treatments, but decreased with AVG and Zn +AVG treatments. Red color development was retarded with both AVG and Zn + AVG treatments, but stimulated with Zn treatment. SSC significantly decreased in the last measurement date (12 August) with AVG treatment. Compared to control fruits, AVG and Zn +AVG-treated fruits had higher titratable acidity, total phenolics and total antioxidant capacity, but Zn-treated fruits had lower values. All micro element and nitrogen and phosphorus-like macro element contents of single Zn and AVG or Zn +AVG-treated fruits were higher than the control fruits. It was concluded that beside AVG, Zn could also play an active role in retarding pre-harvest fruit drops. (C) 2016 Elsevier B.V. All rights reserved.