The lettuce is a plant that features great variability in form, color and texture. The butterleaf variety had remained one of the most consumed lettuce types. The evaluation of leaf type for commercial characters is essential for the development of any improvement program, especially when the parents are divergent types. Furthermore, most cultivars are susceptible to heat. Thus, the objective of the present work was to evaluate F4 progenies of butterleaf lettuce, aiming to select new genotypes for nematode resistance, tolerance to heat and LMV. Twenty-two F3:4 progenies were originated from crosses involving the 'Regina 71' and 'Salinas 88' cultivars, previously selected for heat tolerance, nematode resistance and LMV (lettuce mosaic virus). The experiment was carried out in a randomized block design, with four replications. The limb, edge, head formation and the number of days until flowering were evaluated. Among the 22 evaluated progenies, three are butterleaf and may lead to new lettuce lines resistant to root-knot nematodes, heat and LMV.
Lactuta sativa L.; heat tolerance; butterhead