Effect of two structural analogues of 1-methylcyclopropene on ethylene-induced ripening of avocado fruits

Two structural analogues of 1-methylcyclopropene (I-MCP), named 1-ECP and 1-PCP, were found to delay the ripening of avocado fruits. They exert their effect in a concentration-dependent manner. Treatment for 24 h with 1-ECP (0.5 or 1 mul(.)L(-1)), prior to a 24 h exposure to ethylene (300 mul(.)L(-1)), delayed the ripening of both 'Hass' and 'Fuerte' fruits by 8 and 10 days respectively, as compared with fruit treated only with ethylene. Treatment with 1-PCP (0.3 or 1 mul(.)L(-1)) delayed the ripening of 'Hass' fruits by 7 and 10 days, respectively. Treatment with 1-PCP (1 and 1.5 mul(.)L(-1)) delayed ripening of 'Fuerte' fruits by 8 days. All fruit treated with the inhibitors ripened normally at the end of the inhibition period. The results show that the two compounds are potent inhibitors of ethylene action. As the inhibitors are volatile, non-corrosive and odorless compounds, they can be considered as candidates for practical use.