Effect of 1-methylcyclopropene on ripening of melting flesh peaches and nectarines

1-Methylcyclopropene (1-MCP), an ethylene action inhibitor, was applied to early season, melting flesh stone fruit to try to extend their shelf life. 'Almog' and 'Oded', two white flesh peaches, and 'April Glow', a yellow flesh nectarine, were tested. Application of 1-MCP was at both 20 and 0 degreesC for 5, 10 and 20 h and at concentrations from 0.5 to 20 mul l(-1). When treated at 0degreesC the fruits were stored for 5 days before removal to 20degreesC for ripening. 1-MCP slowed fruit softening in a concentration and time dependent manner, extending the period before the fruits became over-soft. The inhibition of softening was greater when fruits were treated and held at 20degreesC than if they were treated at 0degreesC and held for 5 days at 0degreesC before ripening at 20degreesC. Five mul l(-1) of 1-MCP for 20h was the optimum concentration and time of treatment for inhibition of softening. Ethylene production in peaches was not inhibited by 1-MCP at 20 degreesC but was inhibited after application at 0degreesC. Respiration and soluble solids content were not affected by 1-MCP treatment. Titratable acidity loss was inhibited by 1-MCP in both 'Almog' and 'April Glow', but the low-acid cultivar 'Oded' was not affected. When fruit from two harvests, early and late, were examined for their response to 1-MCP, softening was slower in fruit from both harvests. It appears that 1-MCP in high concentrations can extend shelf life of rapidly softening, perishable fruits such as early season, melting flesh stone fruit. (C) 2003 Elsevier B.V. All rights reserved.