Effect of Alternating Light Quality on the Vegetative and Reproductive Growth of African Violet (Saintpaulia ionantha Wendl.)

African violet (Saintpaulia ionantha Wendl.) belonging to the family Gesneriaseae is a very popular indoor plant. The aim of this study was to investigate the effect of red, blue, red and blue light (one part blue and three parts red) and white fluorescent on the vegetative and reproductive growth of African violet plants. The experiment was conducted in a completely randomized design with 4 treatments and 16 replications in the first phase and 16 treatments with 4 replications in the second phase. The tallest plants in the first and second phases were those treated with red light with an average of 8.2 and 12.5 cm, respectively. Plants treated with mixed blue and red light produced the highest leaves/plant in the first phase of the experiment. However, these plants reduced their number of leaves in the second phase when treated with the blue light. In the first phase, the fluorescent and red light alone developed the greatest canopy area (about 350 cm2), while in the second phase, the canopy area in fluorescent light reached its maximum rate (500 cm2). Similar results were observed for the leaf area. Blue light produced the highest flowers/plant in the first phase, although in the second phase, plants transferred from fluorescent light to the mixed blue and red light indicated increases in flowers/plant. The overall results of the experiment indicate that the blue light plays an important role in early flowering and the red light has an important effect on the rate of canopy extension.