Giora Zauberman - Department of Fruit and Vegetable Storage, Institute for Technology and Storage of Agricultural Products, Agricultural Research Organization, The Volcani Center P.O.B. 6, Bet Dagan 50250, Israel
Yoram Fuchs - Department of Fruit and Vegetable Storage, Institute for Technology and Storage of Agricultural Products, Agricultural Research Organization, The Volcani Center P.O.B. 6, Bet Dagan 50250, Israel
Uri Yanko - Department of Fruit and Vegetable Storage, Institute for Technology and Storage of Agricultural Products, Agricultural Research Organization, The Volcani Center P.O.B. 6, Bet Dagan 50250, Israel
Miriam Akerman - Department of Fruit and Vegetable Storage, Institute for Technology and Storage of Agricultural Products, Agricultural Research Organization, The Volcani Center P.O.B. 6, Bet Dagan 50250, Israel

Ripening of mature avocado fruit was accelerated by 18- and 24-hr ethylene treatments which were applied beginning 1 hr after harvest. Exposure to ethylene for 12 hr or less, starting 1 hr after harvest, did not accelerate the respiration rate, ethylene evolution, or fruit softening. Ethylene treatment for 6 hr starting at 1, 6, 12, or 18 hr after harvest did not accelerate the onset of the ripening process. It is suggested that ethylene does not just "trigger" the ripening of avocado fruit but rather is involved in a relatively long (18 to 24 hr) process which requires its continuous presence.