Lettuce cultivars cultivated under greenhouse were evaluated with the application of cattle manure mixed to sawdust in Alta Floresta, Mato Grosso State, Brazil. The experimental design was randomized blocks in a factorial scheme with 12 treatments and four replications. The treatments consisted of combinations of six cultivars (Lucy Brown, Great Lakes, Isabela, Vera, Elisa and Babá de Verão) and two sources of organic material - cattle manure (100%) and cattle manure mixed to sawdust (50% manure + 50% sawdust composte) - applied at the level of 10 L m-2. Plots measured 1.2 x 1.2 m with 16 plants spaced by 0.3 m over the useful area. Samples were constituted by the four central plants in each plot. Application of bovine manure mixed to sawdust reduced fresh mass, stem length, plant diameter, commercial leaf number and total leaf number when compared to the application of pure manure. Although the cultivars Elisa and Babá de Verão presented higher total and commercial leaf number, it did not reflect in higher commercial mass. The cultivar Lucy Brown presented the highest commercial fresh mass.
Lactuca sativa L.; saw dust; greenhouse; manure; competition