Genotypic Variation in the Postharvest Performance and Ethylene Sensitivity of Cut Rose Flowers

Natural variation in the postharvest quality and longevity of ornamental plants can often be related to differences in their response to ethylene. In the present study, we determined the postharvest performance and ethylene sensitivity of cut flowers from 38 cultivated Hybrid Tea rose genotypes. The vase life of the cultivars varied considerably from 4.5 to 18.8 days at 21 degrees C. There was also substantial variation in the degree of flower opening among genotypes. Exposure to 1 mu L.L-1 ethylene for 24 h at 21 degrees C reduced the longevity of 27 cultivars by 0.8 to 8.4 days (18% to 47%) by accelerating petal wilting and abscission. Ethylene treatment also significantly reduced rates of flower opening in 17 sensitive cultivars and in six cultivars that showed no ethylene-related reduction in vase life. Five cultivars showed no reduction in vase life or flower opening in response to ethylene exposure. Pre-treating stems with 0.2 mm silver thiosulfate liquid or 0.9 mu L.L-1 1-methylcyclopropene (1-MCP) gas for 16 h at 2 degrees C reduced the deleterious effects of ethylene. The release of 1-MCP from two sachets containing EthylBloc (TM) into individual shipping boxes also protected flowers against ethylene applied immediately after a 6-d commercial shipment. The duration of protection afforded by the 1-MCP sachet treatment was greatest when flowers were maintained at low temperature.