Aminoethoxyvinylglycine and 1-methylcyclopropene treatments affect fruit quality and ethylene production in ‘Geum Hwang’ peach

This study evaluated the effect of preharvest aminoethoxyvinylglycine (AVG) and postharvest 1-methylcyclopropene (1-MCP) treatments on ethylene production in association with fruit quality changes during ‘Geum Hwang’ peach ripening. 75 mg L⁻¹ of AVG solution was sprayed to peach trees 7 days before harvest, and 1 µL L⁻¹ of 1-MCP gas was fumigated to fruits at harvest. Untreated peaches were used as a control. All samples were stored for 12 days at 8 °C, and analyses were performed at 4-days intervals. In terms of fruit quality, ethylene production and respiration rate levels in control fruits were 52.1% and 42.2% higher than in AVG-treated fruits and 53.2% and 45.5% higher than in 1-MCP-treated fruits, respectively, at the end of the storage period. The titratable acidity and flesh firmness values were 18.2% and 24.6% higher after AVG and 18.3% and 29.5% higher after 1-MCP treatments than in control samples. On day 8 of storage, lower peel color L* (13.5%) and b* (29.7%) values and higher soluble solids content (6.1%) were observed after 1-MCP but not AVG treatment. However, the peel color a* value was not affected by any treatment. In molecular analyses, AVG and 1-MCP reduced the expression of genes, such as 1-aminocyclopropane-1-carboxylate (ACC) synthase (PpACS1), ACC oxidase (PpACO1), ethylene-response sensor (PpERS1), and ethylene-insensitive 3 (PpEIN3). Additionally, the AVG treatment decreased the expression of PpACS1 (28.6%) on day 4 and PpACO1 (11.2% and 20.5%) and PpERS1 (34.6% and 21.4%) on days 4 and 8 compared to the 1-MCP treatment. In conclusion, AVG and 1-MCP treatments extended the storability and maintained the quality of ‘Geum Hwang’ peaches, with AVG displaying a more significant inhibitory effect, particularly, on the ethylene-related gene expression levels.