Effect of Photoperiod and Light Intensity on Flowering in Sugarcane

Photoperiods of 9, 11, and 14 hr drastically reduced the number of panicles that emerged in several sugarcane clones (Saccharum spp.), as compared to a photoperiod of 12.5 hr. A light intensity of 1399 lux tended to reduce the number of panicles that emerged more than light intensity of 86 lux when the photoperiod was 12.5 or 14 hr. The higher light intensity (1399 lux) caused significantly greater delay of panicle emergence than the lower light intensity (86 lux). Increasing the duration of the 12.5‐hr photoperiod from 0 to 12 weeks resulted in increased delay of panicle emergence; and 4 weeks of this treatment caused maximum delay when started as inflorescences were just beginning to form or were up to 1.25 cm long.