Effect of supplementary lighting on selected physiological parameters and yielding of tomato plants

Light is one of the basic factors needed by plants for their development. The aim of this study was to measure the effect of supplementary lighting of tomato plants with HPS and LED lamps on the chosen physiological parameters and yielding of autumn-winter cultivation crops. Two tomato cultivars (‘Komeett’ F1 and ‘Starbuck’ F1 by De Ruiter Seeds) were used in this experiment. After the plants were planted, LED and HPS lamps of 100 μmol m-2 s-1 light intensity were installed. The results show that the introduction of a supplementary light source to tomato cultivation caused an increase in the intensity of photosynthesis, transpiration, stomatal conductance and chlorophyll by 57.7%, 17.1%, 39.3% and 24.4% on average, respectively. Higher values of those parameters were obtained with HPS lamps than with LED lamps. The amount of marketable crops, number of fruits and mean fruit weight were higher in both combinations in which supplementary lighting was applied, and the values of these traits were higher when the cultivation was supplementary lighted with HPS lamps than with LED lamps. Due to the overhead light configuration and continued low light output, there was no increase of efficiency when using LED lamps compared to HPS lamps despite better focusing and spectral distribution.