Tuesday, August 9, 2016: 9:30 AM
Capitol South Room (Sheraton Hotel Atlanta)
This study was conducted to determine the effects of red (600 – 700 nm) to far-red (700 – 800 nm) ratio during night interruption on vegetative growth in Cymbidium cultivars to reduce production period and improve plant quality. We grew three-month-old Cymbidium cultivars, ‘Yangguifei’, ‘Wine Showe’, ‘Polaire’, and ‘Happy Day’ in a greenhouse which is located in Gongju, Chungnam Province (36o22’1.9”N 127 o04’32.4”E) under natural photoperiod and temperature. Light intensity of all NI lighting treatments was fixed at 129±5 µmol·m−2·s−1. Light with R:FR ratio (0.8, 1.2, 1.5, and 2.2) or red 100% (R) were provided by using red LEDs (peak = 660 nm) mixed with far-red LEDs (peak = 730 nm). A pseudobulb diameter in all cultivars grown under NI was higher than those grown under non-NI treatment. The pseudobulb diameter was the greatest when the plants were grown under R in ‘Yangguifei’ and ‘Wine Showe’. However, there were no differences among NI treatments in ‘Happy Day’ and ‘Polaire’. Overall, leaf length of ‘Yangguifei’,‘Polarie’, and ‘Happy Day’ grown under NI treatments increased as R:FR ratio decreased. However, the leaf length of ‘Wine Showe’ was the greatest under R:FR 1.5, which is similar to R:FR ratio found in natural solar light. We conclude that R:FR ratios in high intensity NI lighting could control vegetative growth of Cymbidium, although responses to R:FR ratio varied depending on cultivars. Therefore, further detailed studies are needed to characterize the effects of R/FR ratio during NI lighting in Cymbidium cultivation.