Produção e tolerância ao pendoamento de alface-romana em diferentes ambientes1

This paper aims to evaluate the influence of different environments and spacings in the production and tolerance to early bolting of romaine lettuce cultivar Sophia. The experimental design used was a randomized block design in a 2x5 factorial design, with two spacings (30x30 cm and 25x25 cm) and five protected environments (with 30% and 50% shade screens, 30% and 50% thermo-reflective screens and an open field), totaling ten treatments with four replicates each. The plots consisted of four rows with five plants each, totaling twenty plants per plot. The six central plants were considered as useful area for yield evaluation. The plots that used the spacing 30x30 cm had 1.8 m^sup 2^ each, and the 25x25 cm plots had 1.5 m^sup 2^ each. Seedlings were transplanted at 26 days and the crop was harvested 46 days after transplanting. The 25x25 cm spacing between plants and the open field provided the highest yield of romaine lettuce.