The combination of ethoxyquin, 1-methylcyclopropene and ethylene treatments controls superficial scald of 'd'Anjou' pears with recovery of ripening capacity after long-term controlled atmosphere storage

Superficial scald is the most devastating storage disorder of 'd'Anjou' pears (Pyrus communis L.) and the current commercial controlling method of ethoxyquin (Etq) + controlled atmosphere (CA) storage is not adequate for the fruit produced in hot seasons. In the hot years of 2014 and 2015, 'd'Anjou' pears were harvested at commercial maturity and treated with Etq at 2700 mg L−1, 1-methylcyclopropene (1-MCP) at 0.3 μL L−1 along or in combination with ethylene at 0.3, 0.6, or 1.5 μL L−1 (M+E: 1:0, 1:1, 1:2, and 1:5, respectively), and the combination of Etq plus M+E (1:1), and then stored in CA (1.5 kPa O2, <0.5 kPa CO2) at −1.1 °C for 8 months. The non-treated control fruit developed 82% and 100% scald after 4 and 6 months storage, respectively. Etq-treated fruit developed unacceptable level of scald (>10%) after 6 months. M+E (1:0) treatment inhibited ethylene production, prevented scald through decreasing the syntheses of α-farnesene and conjugated trienols, maintained fruit firmness and green color, and reduced decay; however, inhibited ripening capacity following 8 months storage. Compared with M+E (1:0), M+E (1:1 or 1:2) treatments allowed fruit recovering ripening capacity but decreased efficacy on controlling scald; Etq plus M+E (1:1) could control scald <5% for 8 months. M+E (1:5) largely offset the 1-MCP efficacy. In summary, the combination of Etq plus M+E (1:1-2) controls scald, extends storage quality, reduces decay, and allows recovering of ripening capacity of 'd'Anjou' pears after long-term CA storage.