Effects of aminoethoxyvinylglycine (AVG) on preharvest fruit drop, fruit maturity, and quality of 'Red Chief' apple

AVG was applied as the 'ReTain' formulation to determine its effects on preharvest drop of 'Red Chief' apple. AVG applications (150, 300 and 600 mg/L) made 4 week before anticipated harvest decreased significantly preharvest drop ratio and ethylene production relative to control. AVG delayed fruit ripening and slowed loss of flesh firmness and degradation of starch. The removal force of fruits treated AVG were greater than those of fruits from control and NAA treated trees at all harvest dates. Two application of NAA made 4 and 2 week before anticipated harvest was ineffective to control preharvest drop in 'Red Chief' apple. NAA increased ethylene production of fruits one week after second application, but did not cause a significant difference at normal harvest date relative to control. Among three AVG concentrations, only 600 mg/L AVG increased significantly L* and hue angle value relative to control. All AVG concentrations used had no effect on chroma value. NAA did not cause a significant effect on chroma and hue angle values, but decreased L value compared to control.

► AVG slowed loss of flesh firmness and degradation of starch. ► Fruit removal force was higher in fruits treated with AVG than control at all harvest dates. ► NAA increased ethylene production of fruits one week after second application. ► AVG decreased ethylene production of fruits at final harvest. ► Only 600 mg/L AVG increased significantly L* and hue angle value relative to control.