Programacion de la produccion de Lisianthus russellianus L.

Lisianthus is a quantitative long day plant: plants flower faster under long-day (LD), but eventually flower regardless of photoperiod. A research was conducted in order to evaluate the effects of photoperiodic lighting on plants grown at two different density and ways of growing. The experiment was carried out in a heated greenhouse (set point 18 °C). Plants of Lisianthus russellianus cv Echo yellow (double flower) were transplanted on sandy soil. The following treatments were compared: 2 plant density: 40 and 70 plants/m2; 2 ways of growing: pinching at the third internode and no pinched control; 2 photoperiodic regimes: natural day and long day (16 hours). Photoperiodic treatment was applied from the transplanting until the harvest, with continuous lighting, using incandescent lamps (150 Watt). The highest plant density did not affect the time of flowering while the stem production was 1.5 times higher at 70 plants/m2, with no significant variation in cut stem characteristics. Pinching delayed the beginning of the harvests compared with the no pinched control (3 weeks). Flower stems production was 2.5 times higher when plants were pinched but the single-stem plants gave the best quality. Photoperiodic treatment determined an earlier production compared to the control under natural lighting conditions (-12 days) but reduced the number of flowers per stem.