An experiment was carried out at Fazenda Água Limpa - University of Brasilia (Brazil), in a glasshouse environment, to evaluate yield response of three lettuce cultivars, Verônica, Ame ricana Tainá and Elisa under hydroponic conditions (NFT system). The formula used in the nutrient solution was prepared with 550 g of magnesium sulfate, 950 g of calcium nitrate, 810 g of potassium nitrate, 115 g of MAP, 3 g ofboric acid, 0.2 g of sodium molibdate, 2 g of manganese sulfate, 0.15 g of copper sulfate, 0.2 g of zinc sulfate and 60 g of Ferrilene (EDDHA) for 1000 It of nutrient solution. The plants were transfered to the hydroponic system 20 days after the sowing date and harvested 36 days later. The experi mental design was completely randomized with three treatments and 25 plants per treatment. There was no significant difference between cultivars in plant weight. The average weight was 183.4 g for Verônica Crespa, 182.53 g for Elisa and 175.84 g for America na Tainá. A significant difference was observed between cultivars in the number of leaves per plant. The cultivar Elisa showed 22.12 leaves per plant and the cultivar Verônica Crespa 13.31 leaves per plant. The three cultivars showed a satisfactory performance under hydroponic conditions.
Lactuca sativa; hydroponic; NFT system; yield.