Interactions of flower stage, cultivar, and shipping temperature and duration affect pot rose performance

Simulated shipping (storage) experiments were conducted to determine the effects of shipping temperature and duration on flower longevity and leaf abscission of pot rose Rosa L. 'Meijikatar' (= Orange Sunblaze) and 'Meirutral' (= Red Sunblaze), In addition, three flower stages (1 = tight bud, calyx not reflexing; 2 = showing color, calyx reflexing, no petals reflexed; 3 = full color, petals beginning to reflex, traditional bud stage) were selected immediately prior to storing plants at 4, 16, or 28 degrees C for 2, 4, or 6 days. The experiment was conducted during the summer and repeated during the winter. Evaluations were made in an interior environment at 21 degrees C for both experiments. 'Meirutral' exhibited longer poststorage longevity and less leaf abscission than 'Meijikatar' in both experiments. Flowers of both cultivars advanced by about one stage during storage at temperatures greater than 4 degrees C in summer, but developed more slowly in winter. Results from both experiments showed that plants stored at 4 degrees C had the longest poststorage floral longevity, the best flower quality, and the least leaf abscission, regardless of cultivar, storage duration, or flower stage at the beginning of storage. For plants stored at 16 degrees C, floral longevity decreased and leaf abscission increased when the duration was longer than 4 days. At 28 degrees C, flower longevity decreased and leaf abscission increased, especially at durations longer than 2 days. In the winter experiment, there was no leaf abscission on plants placed in the dark at 21 degrees C and watered during storage treatments lasting up to 6 days. In the summer experiment, the younger the flower, the more it was negatively affected by high storage temperature. Overall, poststorage floral longevity was longer in the summer than the winter experiment.