The Growth and Tuber Yield of Potatoes (Solanum tuberosum L.) under Varying LED Light Spectrums in Controlled Greenhouse Conditions

Plant growing using light-emitting diodes (LEDs) in a controlled environment is a revolutionary and innovative idea, regardless of the external environmental disturbances. Studying the growth and tuber yield of potatoes (Solanum tuberosum L.) in an LED-based plant factory system is a relatively innovative concept. The current study was conducted in a plant factory to evaluate the effects of different LED spectral compositions on potato tuberization. Potato tuberization was analyzed under six different LED light spectral combinations with irradiances of 300 mol m−2 s−1, with natural light considered the control treatment. The findings stated that the L2 treatment (red70 + blue20 + white10) increased the plant height, branch number, and biomass accumulation, while photosynthetic pigments and photosynthetic activity increased significantly in L5 (red60 + blue20 + green10 + white10). Higher gibberellic acid (GA3) content was recorded in L1 (red70 + blue30), whereas the tuber number and tuber fresh weight were recorded in L3 (red70 + blue20 + green10) and L7 (natural light), respectively. On the other hand, a higher number of smaller-sized tubers were observed in L5, while L2 and L4 (red70 + blue20 + far-red10) resulted in a higher number of medium-sized tubers. In conclusion, a high proportion of red and blue light, along with white and far-red light, increased the plant height, branch number, plant biomass, and production of small- and medium-sized tubers. On the other hand, the inclusion of green light with red and blue enhanced the chlorophyll content, photosynthesis, and leaf expansion, and promoted the production of smaller-sized tubers. Finally, with regard to tuberization, the treatment using L4 followed by L2 outperformed the other treatments.