Complex LED light regimens differentially regulate tomato growth, yield formation and fruit quality

Tomato is a very important horticultural crop worldwide, valued for its economic significance and nutritional benefits. Tomato fruits are rich in essential nutrients and bioactive compounds, including vitamins, carotenoids, and polyphenols. In this study, we investigated how light quality and intensity influence plant growth, yield, and fruit quality parameters in tomato. Plants were grown under six different light regimens, including varying red-to-blue ratios, wide spectral white light with or without far-red application at two light intensities (300 μmol m −2 s −1 and 500 μmol m −2 s −1 ). Our results demonstrated that blue light promoted flowering and fruit set, leading to a higher number of fruits; however, under lower light intensity, this resulted in smaller fruits. In contrast, red-dominant or broad-spectrum light conditions produced less but larger and sweeter fruits, even at low light intensity. Higher light intensity overall increased total yield and sugar accumulation, also indicating enhanced photosynthetic activity and preferential allocation of assimilates to fruit biomass. Interestingly, lycopene content was not affected by any light treatment at all. Our findings showed that a careful consideration is required when selecting the intensity and spectral composition of an artificial lighting in indoor cultivation systems.