Mature avocado fruit (Persea americana Mill. cvs ‘Ettinger’, ‘Hass’, ‘Reed’ and ‘Fuerte’), harvested during the commercial harvesting season, were treated with various concentrations of 1-methylcyclopropene (1-MCP) for 24 h at 22°C and after ventilation, were exposed to 300 mll
1
ethylene for 24 h at 22°C. The fruit were then stored at 22°C in ethylene-free air for ripening assessment. Ethylene production, firmness, cellulase (endo-1,4-b-glucanase) and polygalacturonase activity, as well as color change in ‘Hass’ fruit, were monitored during storage. 1-MCP was found to inhibit ethylene-induced ripening of avocado fruit at very low concentrations. Treatment for 24 h with 30–70 nl l
1
www.elsevier.com:locate:postharvbio
1-MCP delayed ripening of avocado fruit by 10–12 days, after which the fruit resumed normal ripening. It is suggested that 1-MCP is a potent inhibitor of avocado fruit ripening which exerts its effect via inhibition of ethylene action. © 2000 Elsevier Science B.V. All rights reserved