Effect of supplementary light on tomato transplant growth, and the after-effects on yield

Abstract

Tomato ( Lycopersicon esculentum Mill.), transplants, cultivars ‘Matador’ and ‘Blizzard’, were grown with supplementary light at photosynthetic photon flux densities of 30, 60 and 90 μmol m −2 s −1 and constant temperatures of 17, 19 and 21°C to determine the effect of supplementary light level on growth and the after-effects on yield, and to examine interactions with cultivar and temperature. Plant height, leaf number, leaf area and dry weight of aerial plant parts were significantly increased with increasing levels of supplementary light. Greater early yield and market value was found with increasing levels of supplementary light prior to planting, due to an increased number of harvested fruit in the early cropping period. The increased yield and market value was maintained throughout the 16 week harvest period. A reduction in fruit quality with increasing levels of supplementary light was found in the early cropping period but no differences were found after 16 weeks of harvest. No significant interactions with temperature or cultivar were found.