Response of climacteric-type guava (Psidium guajava L.) to postharvest treatment with 1-MCP

Guava (Psidium guajava L. cv. 'Allahabad Safeda') fruit harvested at the mature light-green stage were exposed to 300 and 600 nL L-1 1-methylcyclopropene (1-MCP) for 6, 12 and 24 h at 20 +/- 1 degrees C, and held in either cold storage (10 degrees C) for 25 days or ambient conditions (25-29 degrees C) for 9 days. Most of the physiological and biochemical changes during storage and ripening were affected by 1-MCP in a dose dependent manner. Ethylene production and respiratory rates were significantly suppressed during storage as well as ripening under both the storage conditions depending upon 1-MCP concentration and exposure duration. 1-MCP treatment had a pronounced effect on fruit firmness changes during storage under both the conditions. The reduced changes in the soluble solids contents (SSC), titratable acidity (TA) and vitamin C content showed the effectiveness of 1-MCP in retarding fruit ripening. Vitamin C content in 1-MCP-treated fruit was significantly higher than in non-treated fruit, and those treated with 300 nL L-1 1-MCP for 6 h. The development of chilling injury symptoms was ameliorated to a greater extent in 1-MCP-treated fruit during cold storage and ripening. A significant reduction in the decay incidence of 1-MCP-treated fruit was observed under both the storage conditions. 1-MCP at 600 nL L-1 for 12 h, in combination with cold storage (10 degrees C) seems a promising way to extend the storage life of guava cv. 'Allahabad Safeda' while 1-MCP at 300 nL L-1 for 12 and 24 h or 600 nL L-1 for 6 h, may be used to provide 4-5 days extended marketability of fruit under ambient conditions. (c) 2007 Elsevier B.V. All rights reserved.