Respiratory Rate, Ethylene Production, and Ripening Response of Avocado Fruit to Ethylene or Propylene following Harvest at Different Maturities1

Abstract

Abstract The respiratory rate, ethylene production and softening of untreated and treated (propylene or ethylene) avocado fruit (Persea americana Mill, cv Hass) were determined during growth and maturation using fruit harvested monthly from August to July. Untreated immature fruit harvested in August exhibited a climacteric, produced ethylene and softened after 18, 21 and 18.5 days, respectively. Treatment of these immature fruit for 1 to 3 days beginning 1 day after harvest stimulated respiration during the treatment, but the respiratory rate decreased to the level of the untreated fruit within 1 day after the treatment was terminated and they subsequently paralleled the response of the untreated fruit. Ethylene production was not induced by the treatment in immature fruit, but was in mature fruit. The climacteric peak rate and the peak rate of ethylene production increased as the fruit matured. The days to the climacteric peak and days to soften decreased as the season progressed. The ethylene or propylene treated fruit had a progressively shorter time to the climacteric and to softening as they matured compared to the untreated fruit.