Light spectral composition is a key factor in controlling plant growth and tuber quality of potato in controlled environment

In order to elucidate the effect of genetic material and light source and their interaction on plant per- formance of potato (Solanum tuberosum L.), we studied the influence of two light sources, white fluor- escent tubes (WF) and red blue LEDs with ratio 8:1 (RB) and two cultivars, ‘Avanti’ and ‘Colomba’ grown in phytotron, on growth, leaf photosynthesis and photochemistry and tuber quality. Under WF, net photosynthesis (NP) increased from the vegetative phase until flowering, then decreased during tuber bulking, with no differences between the cultivars. Lighting with RB increased the NP and the PSII maximum quantum use efficiency compared to WF. RB reduced stem elongation in both cultivars, as well as the number and area of leaves, and the aerial biomass per plant in ‘Colomba’, compared to WF. Conversely, tuber yield was higher in plants under RB light in both ‘Avanti’ and ‘Colomba’. Light source did not influence the tuber content of starch and total glycoalkaloids, while it affected differ- ently in the cultivars the protein content and the glycoalkaloid profile. Our results highlight how inter- actions between light source and genotype need to be considered for potato cultivation in controlled environment under artificial lighting.