Abstract
As a problem associated with the cultivation of lettuce, the growth of stem and floral stage are facilitated under a high temperature, which will eventually reduce its quality. To address this problem, cultivation under low-temperature conditions is considered. However, it is difficult to cultivate lettuce while controlling the temperature because of the production cost, and growth control technologies based on photo-morphogenesis are attracting attention. An experiment was conducted on the growth control of lettuce under a high-temperature involving End-of-day light irradiation using LED light source. The seeds of lettuce were sown on January 16 and August 23, 2012, and the plants were placed under a high temperature (30°C) and exposed to the light on January 22 and August 28, 2012. Far-red and red LED lights were used as light sources. No light source for irradiation treatment was placed in the third treatment, as the control. Sixty days after the treatment of Manoa by the far-red light treatment, the stem length was the longest, and the floral stage was the highest. The results of the experiment on lettuce cultivation under a high-temperature suggest that End-of-day light irradiation using LED light source effectively controls the growth of lettuce.
