Sensitivity of Avocado Fruit to Ethylene

The respiration of individual 'Hass' and 'Fuerte' fruit was monitored during storage at 8oC and 10oC respectively for 14 days, under a continuous flow of humidified air containing ethylene (C2H4) at 0, 0.01, 0.05, 0.25, 1.0 and 5.0 μL.L. Respiration rates of 'Fuerte' fruit under 0.01 μL.L C2H4 were significantly higher than the controls after 3.3 days of storage, but for 'Hass' fruit respiration rates did not become significantly higher until under 1.0 μL.L for 5.7 days. In another experiment, 'Hass' fruit were held in the presence of 0, 35, 70, 140, 280 or 1000 g of Purafil® (C2H4 absorbent) at 20oC. Increasing amounts of Purafil® consistently reduced the maximum concentration of C2H4 detected in the storage containers. Days from harvest to maximum detected C2H4 production rate (MDEPR) in bulk samples was increased from 8.1 to an average of 11.1 days by the presence of Purafil®, but increasing amounts of Purafil® had no further effect. Fruit stored individually in ventilated containers in the absence of Purafil® reached MDEPR on average at 13.8 days. These results indicate that stimulation of ripening by C2H4 evolution from earlierripening fruit may be important in hastening ripening of fruit stored in bulk. Ethylene removal in storage may offer some advantage, but concentrations may need to be reduced to 0.05 μL.L or lower to obtain significant benefit, especially for 'Fuerte'. However, storage of only those fruit with similar storage capacity is likely to be of greater benefit. A knowledge of production factors contributing to poor storage life is required.