Production of crisped lettuce cultivars under different depths irrigation

This study aimed to evaluate the production of different cultivars of crisped lettuce under different irrigation depths in northeastern Mato Grosso do Sul State, Brazil. The experiment was conducted in a split plot scheme, with the four installments water depths (50, 75, 100 and 125% of crop evapotranspiration - ETc) and the subplots three crisped lettuce cultivars (Rapids. Monica and Simpson), the design a randomized block design with four replications. Irrigation was applied via drip system and irrigation management using the reference evapotranspiration by Penman-Monteith method. The following characteristics were evaluated: plant height, head diameter, number of leaves per plant, fresh weight of roots, dry weight of roots, shoot fresh weight, shoot thy weight, plant fresh weight, plant dry weight and water use efficiency. Increased irrigation regimes provided reductions in the water use efficiency and increase in shoot fresh weight. The irrigation depth of 103.6% ETc maximized the head diameter of three lettuce cultivars (Rapids, Monica and Simpson). For other factors, it was found best results with water depths of 125% ETc. The Simpson lettuce is a promising cultivar for the study area and should be irrigated with depth of 100% ETc. Lettuces Rapids and Monica should be preferred by producers of northeastern Mato Grosso do Sul State and irrigated with replacement of 125% ETc.