Use of very low ethylene levels to extend the postharvest life of Hass avocado fruit

Unripe Hass avocados were stored at 0, 10 and 20°C in air containing ethylene at concentrations ranging from 1.0 μl l‐1 down to 0.005 μl l‐1. The time to ripen of fruit held continuously at 10 and 20°C increased linearly with a logarithmic decrease in ethylene concentration. Fruit held at 0°C were transferred to 20°C after 2, 4 and 6 weeks and allowed to ripen. While there was no effect of ethylene concentration on ripening time, the severity of chilling injury on fruit held at 0°C for 4 and 6 weeks was reduced with decreasing log ethylene concentration. Analysis of avocados in the wholesale markets at ambient temperature showed an average presence of ethylene at 0.16 μl l‐1. An increase in storage life would be achieved if levels of ethylene currently present during marketing were reduced.