Influence of light quality on morphology, flower and tuber formation of the potato plant (S. tuberosum).

MSc thesis abstract (submitted 12 February 2015):
Recently, the growth and development of the potato plant (Solana tuberosum L.) has reached great attention, with breeding companies focusing on the introduction of new alternative propagation methods using true potato seeds rather than potato tubers.

In this experiment, the influence of light quality on growth and development of the potato plant are assessed. Main focus is given on flowering and tuberization. The experiment was performed in long day conditions (16 hours daily light supply) with four different light treatments using light emitting diodes (LEDs). In these light treatments the effect of far-red light was determined. The experiment consisted of a control treatment with white light, two light treatments with white light and additional high and low intensity far-red light supply during the day, respectively, and a treatment with white and end-of-day (EOD) low intensity far-red light. Three cultivars were used, the Solanum tuberosum spp. andigena, an obligate short day plant for tuberization and two day-neutral genotypes, G254 and RH89-39-16.

The results indicate that high far-red light intensity during the day and EOD far-red light treatments promote earlier tuber formation. The higher far-red light intensity during the day was also responsible for enhanced stem elongation. However, flower appearance moments, leaf area and leaf number are not affected by enhanced far-red light supply. The dry weight is increased under high far-red light intensity. The starch leaf content is associated with the tuber production, whereas sucrose doesn’t show clear influences on the processes.