Ethylene production of Botrytis cinerea, kiwi fruit and Botrytis rotted kiwi fruit under several storage temperatures

Gray mold (Botrytis cinerea, Pers) causes a rot of kiwifruit and this is a serious threat in the new growing kiwifruit industry in Greece. Many postharvest losses occurred in 1989, due to the rotting and the early softening of the kiwifruit. The present study was undertaken to investigate in "Hayward" kiwifruit the possible involvement of fungus in ethylene production and the effect of temperature on growth of gray mold and ethylene production. In one experiment Botrytis cinerea incubated in PDA placed in a closed system at 0 degrees, 5 degrees, 10 degrees and 20 degrees C produced almost negligible amount of ethylene 20 days after inoculation of the medium. In another experiment kiwifruit inoculated with Botrytis and placed in a continues flow system at 0 degrees, 5 degrees and 10 degrees C produced considerable amount of ethylene 20 (10 degrees C) 30 (5 degrees C) and 150 (0 degrees C) days after inoculation. During the same period the control (healthy) and wounded fruit produced very small amount of ethylene. The infected kiwifruit produced more ethylene at 5 degrees or 10 degrees C than at 0 degrees. This emphases the importance of avoiding infections by Botrytis of kiwifruit. The fungus induces the fruit to produce ethylene through the methionine pathway and this infected fruit is able to induce premature ripening of the healthy fruit in commercial storage.