Selection of cut flower species affected promotion of flowering and stem elongation by far-red lighting or heating treatments on end of day under limited sunshine from autumn to winter

The effect of a brief exposure to treatments of end-of-day (EOD) far-red (FR) light and EOD-heating on flowering and stem elongation in certain species cultivated in areas with limited sunshine from autumn to winter has been investigated. Thirteen EOD-FR treated cultivars among all 24 cultivars tested in experiment 1, showed earlier flowering than control plants. Additionally, Kanzaki No.21, F1 Winter cherry and Gypsy deep rose were earlier to flower under the all night-FR treatment than under the EOD-FR treatment. Further, 13 cultivars among all cultivars tested in experiment 1 showed greater stem length, whereas 16 cultivars of them showed greater mean internode length than controls when treated with EOD-FR. The days to flowering in 13 cultivars treated by EOD-Heating, flowering was earlier than in controls. Also, stem length and mean internode length were also promoted by the same treatment in 7 cultivars. Additionally, flowering and stem elongation of Stella rose, Arizona sun, Suzuhime and Extra carmine rose were promoted by a combination of both treatments, and productivity and quality were improved. These results suggest that the treatments tested can help the production of cut-flowers in areas with limited sunshine from autumn to winter, although the method of application of the treatments must be optimized for each species.