Growth Responses in Leaf Lettuce Cultivar Grown under Different Qualities of Light from LED Sources

Abstract

The growth and yield of 12 different leaf lettuce (Lactuca sativa L.) cultivars were evaluated under different qualities of light produced by LEDs. Red leaf lettuce cultivars showed a tendency of increasing growth under a mixed light source of blue and red LEDs. On the other hand, in the case of green leaf lettuce cultivars, there was no clear difference in growth under different light qualities. Under lights including the blue spectrum, the stem elongations of all cultivars were suppressed compared with those irradiated by red LEDs. Based on those results, red and blue lights have antagonistic effects, promotion and suppression, respectively, on stem elongation of lettuce. Therefore, there was a difference in reaction characteristics due to LED light quality in each variety of lettuce.