Effect of different light sources in in vitro on growth, morphology and minituber production of potato (Solanum tuberosum L.) in hydroponic conditions

In order to evaluate the effect of different light quality, on the growth of potato plantlets in vitro, and their subsequent performance in the greenhouse, an experiment was performed in 2015 in Mashhad, in tissue culture laboratory and greenhouse of Yekta Seed Technology Company. A factorial experiment based on the completely randomized design with six replications performed. The first factor consisted of eight different light treatments as follows: white, red and blue Light-emitting diode (LED), combination of red and blue spectrum ratios of 1:1, 1:3 and 3:1, fluorescent lamp and natural light and the second factor was two potato cultivars including Agria and Fontane. MS culture medium was used for micro propagation of plantlets and plants fed with Hoagland nutrient solution in the greenhouse. After four weeks, the seedlings were removed from the culture medium, and their morphological properties were assessed and then plantlets transferred to the greenhouse and were grown in hydroponic condition for 90 days.Results showed that Agria in vitro plantlets were taller than the Fontane plantlets. Natural light produced the highest leaf area and the lowest leaf area was produced in blue spectrum. By increasing the red spectrum, number of tubers of both cultivars significantly increased and the weight of tubers per plant decreased. Fluorescent light source produced the lowest number of tubers per plant in both cultivars. By increasing ratio of red spectrum, potato plants produced higher tuber number with the smaller size and weight.