The effect of 1-methylcyclopropene (1-MCP) treatment on improving the storability of four apple cultivars (‘Hwangok’, ‘Picnic’, ‘Gamhong’, and ‘Fuji’) was investigated by analyzing the physiological and biochemical factors associated with their postharvest quality attributes. The flesh firmness, titratable acidity, and soluble solids content of the cultivars were higher in treated fruits than untreated fruits, while the opposite results were observed for ethylene production. In the treated fruits, the traits affected by 1-MCP varied depending on the cultivars used. Higher firmness and lower ethylene production were observed in the ‘Hwangok’ and ‘Picnic’ than ‘Gamhong’ and ‘Fuji’ cultivars. However, 1-MCP only affected weight loss in the ‘Gamhong’ cultivar, while the sugar content was affected in all of the cultivars except ‘Hwangok’. When analyzing cell wall hydrolase activities, 1-MCP differently affected the activities (β-galactosidase, α-galactosidase, β-glucosidase, α-mannosidase, β-xylosidase, and β-arabinosidase), with greater effects in the ‘Fuji’ and ‘Picnic’ cultivars and moderate effects in the ‘Gamhong’ and ‘Hwangok’ cultivars. In this study, the suppression of ethylene production by 1-MCP was positively associated with a transcriptional decrease in the ethylene biosynthesis genes MdACS1 and MdACO1. Overall, this study suggests that 1-MCP distinctly enhanced the storability of all apple cultivars, with a greater effect on ‘Hwangok’.

The efficacy of 1-methylcyclopropene (1-MCP) in maintenance of apple fruit quality can differ depending on apple cultivar, ethylene content at harvest, 1-MCP concentration, the interval between harvest and 1-MCP application, and the number of applications. In this study, we investigated whether the 1-MCP concentration and its application frequency differently affected fruit quality attributes of the two new apple cultivars ‘Arisoo’ and ‘Picnic’. The fruits were treated with 1-MCP (as single or double treatments) at the rate of 0 μL L⁻¹ (control), 0.5 μL L⁻¹, 1 μL L⁻¹, 0.5 + 0.5 μL L⁻¹, and 1 + 1 μL L⁻¹ for 18 h, and they were stored at 0 °C up to six months. Comparatively, the fruit qualities of 1-MCP treated fruits were higher than that of the control during cold storage, with a higher suppression of internal ethylene content and a slower reduction of titratable acidity in 1-MCP treatments than the controls throughout the cold storage in both cultivars, regardless of the concentration and number of applications. Reduction of fruit firmness and soluble solid contents were maintained by single application of 0.5 μL L⁻¹ 1-MCP in ‘Arisoo’ apple, while double application of 0.5 + 0.5 μL L⁻¹ was needed in ‘Picnic’ cultivar. The effective concentration for weight-loss reduction was found to be the single application of 1 μL L⁻¹ 1-MCP in both ‘Arisoo’ and ‘Picnic’. Conclusively, 1-MCP as single treatment at the rate of 0.5 μL L⁻¹ could be sufficient in inhibiting ethylene action and maintaining fruit quality losses during cold storage, particularly in ‘Arisoo’. However, double application of 1-MCP might be necessary for some quality attributes in ‘Picnic’ apple.