With the objective of studying the effect of water salinity on the productivity of lettuce, cv. 'Elba', an experiment was carried out in a completely randomized design, under a protected environment. Five levels of water salinity (ECw: 0.3, 1.0, 1.7, 2.4 and 3.1 dS m-1 at 25 ºC) and two types of seedlings (produced using water of 0.3 and 3.1 dS m-1) were tested. The effects of the factors on the fresh and dry weight of the aerial parts, number of leaves, diameter of the head, and dry weight of roots, were evaluated. It was concluded that the studied variables were influenced by ECw and by the seedling types, without being influenced by the factor interaction. The equations, obtained through polynomial regression, relating the variables studied with the salinity levels are also, presented. The relative production (fresh weight) of the cultivar studied, decreased 9.0% for each unitary increment of ECw.
protected environment; phytomass; yield; Lactuca sativa L.
