Performance of three lettuce (Lactuca sativa L.) cultivars in plastic-greenhouse was carried out in Campinas, São Paulo State, Brazil, from July to October 2004. The experiment was set up in completely randomized design with four replicates. Bariri (lengthy leaf lettuce), Mariane (crisp head lettuce) and Verdinha (leafy lettuce) cultivars were evaluated for yield, average plant height and number of leaves at 7, 14, 21 and 28 days after transplantation. Head diameter, foliar area and shoot fresh weight were also obtained at 28 days. The effect of sampling period showed linear response in function of time for average plant height and number of leaves. Number of leaves and foliar area were greater in `Bariri' but `Verdinha' showed greater head diameter. `Bariri', without differing from Mariane, showed greater average plant height than `Verdinha' at 28 days after transplantation. `Verdinha' showed greater head diameter and head fresh weight, without differing from `Mariane' as to this character.
Plastic- protection; Lactuca sativa L.; yield; development
