Abstract
Coloring area ratio in Eustoma picotee petals often increases in the winter, leading to a reduction of commercial value. It has been thought that encountering a low temperature before flowering causes this increase. We studied the effects of temperature on the picotee pattern of ‘Candy Marin’, which is a very early flowering cultivar, using artificial climate chambers under a 12-h light condition. Under constant temperature conditions, the picotee coloring area rate was the highest at 20°C and a negative correlation was found between the rate and growth temperature. Changing daytime and nighttime temperatures to 19°C and 25°C decreased the ratio. Even if the plant encountered 5°C at night, the picotee coloring area rate was kept low by encountering 35°C in daytime, suggesting that day-time treatment at high temperature could avoid increasing the rate in the winter season. The temperature condition reducing the picotee coloring area rate tended to decrease growth amounts as well. We also found that increase in the coloration area ratio is not directly related to an increase in the anthocyanin-flavonoid concentrations.
