L-methylcyclopropene inhibits apple ripening

An ethylene action inhibitor, MCP, was applied to preclimacteric and climac teric apple [Malus sylvestris L. (Mill.) var, domestica Borkh. Mansf.] frui t. Experiments were conducted in North Carolina and Washington State utiliz ing the following cultivars: Fuji, Gala, Ginger Gold, Jonagold, and Delicio us. MCP inhibited loss of fruit firmness and titratable acidity when fruit were held in storage at 0 degrees C up to 6 months and when fruit were held at 20 to 24 degrees C for up to 60 days. For all cultivars except 'Fuji', differences in firmness between treated and nontreated fruit exceeded 10 N after 6 months storage. These beneficial effects were seen in both preclima cteric and climacteric fruit. Ethylene production and respiration were redu ced substantially by MCP treatment. MCP-treated fruit had soluble solids eq ual to or greater than those in nontreated fruit. Storage and shelf life we re extended for all cultivars tested. Chemical name used: 1-methylcycloprop ene (MCP).