Initial Development and Tolerance of Lettuce (Lactuca sativa) Cultivars Irrigated with Saline Water

The objective was to study the initial development and tolerance of lettuce cultivars subjected to different levels of water salinity in the seedling production stage in order to determine the genotypes of the cultivars that are most sensitive and tolerant to saline water. The experiment was carried out in protected environment at the Center of Sciences and Agri-food Technology-CCTA of the Federal University of Campina Grande-UFCG, located in Pombal, Paraíba, Brazil, from August to September 2014. The study evaluated five lettuce cultivars (C1-’Simpson Semente Preta’, C2-’Alba’, C3-’Mimosa Vermelha’, C4-’Veneranda’ and C5-’Mônica Sf 31’) and five levels of irrigation water salinity (0.6 (control), 1.2, 1.8, 2.4 and 3.0 dS m-1), arranged in a factorial scheme 5 × 5, in a completely randomized experimental design, with four replicates. Plants were grown on trays for 20 days after sowing, period in which irrigations were daily applied, and evaluated for emergence, growth, phytomass accumulation and tolerance index of the lettuce cultivars. The increase in irrigation water salinity reduced emergence, growth and dry matter accumulation in the lettuce plants, and the cultivars C2-’Alba’ and C4-’Veneranda’ were the most tolerant to salinity. Tolerance to salinity occurred in the following order C2-’Alba’ = C4-’Veneranda’ > C1-’Simpson Semente Preta’ > C3-’Mimosa Vermelha’ = C5-’Mônica Sf 31’.