Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Grossbeeren, Germany Effects of environmental factors on carotenoid content in tomato (Lycopersicon esculentum (L.) Mill.) grown in a greenhouse*

Tomatoes are an important source of lycopene in the human diet. The effect of temperature (15°C- 24°C), CO2 supply (380- 1000 ppm) and nutrient concentration measured as electrical conductivity of the nutrient solution (EC, 2- 9 dS m-1) on the content of carotenoids (lycopene, ß-carotene) were investigated in two tomato cultivars grown in a greenhouse. The cherry tomato cultivar Supersweet was characterised by higher lycopene contents than the conventional round tomato ‘Counter’. The results indicated that temperature has a significant influence on the biosynthesis of lycopene and ß-carotene during ripening. A temperature above 20°C seems to be optimal for lycopene production in the investigated cultivars, whereas a decrease to 15°C diminished the lycopene content. Neither CO2 supply nor EC increase affected the carotenoid content under the conditions investigated