Phenotyping 33 tomato genotypes grown under different LED light spectra.

MSc-thesis abstract (submitted 22 August 2016): There is an increasing interest in protected environment technologies such as LED lighting, which may contribute to increase horticulture yield and allow a year round production. The objective of this study was to characterize the effect of monochromatic blue LED (100% blue) lighting and UV-B radiation on several morphological and photosynthetic parameters of a wide variety of tomato genotypes.

No interaction was found between pre- and post-harvest treatments. The results showed that post-harvest light treatments did not increase the vitamin C content due to over ripened strawberry fruits and serious fruit weight loss. The weight loss experiment was carried out using three light sources, white and blue (both with 100 μmol m−2 s−1). At the same light intensity, fruits illuminated with blue light had higher weight loss than fruits in white and dark treatments as a result of higher calyx transpiration under blue light.

It is our recommendation that repeating the post-harvest light treatments on fruits AsA content as function of maturity stage may substantiate the hypothesis that there is a maximum AsA level in strawberries. And weight loss experiments manipulating the calyx area, by varying the position of the calyx towards the light source, by limiting the calyx area, or by applying ABA to close the stomata, might substantiate the hypothesis that weight loss is connected to calyx transpiration.

Keywords: tomato, monochromatic blue, light emitting diodes (LEDs), UV-B, phenotyping.