Due to the environmental conditions verified in the state of Acre, characterized by the occurrence of high temperatures and precipitation, cultivars traditionally used by the producers present low yield and poor quality. The aim of the present work was to evaluate the behavior of the new lettuce cultivars available in the market, in terms of agronomic characteristics and yield, in the climatic and soil conditions of Rio Branco. Two trials were accomplished in the Embrapa Acre experimental farm, in a dark red claysoil, of loamy texture. The first from May to July 1996 (dry season) and the second from December 1996 to February 1997 (rainy season). The cultivars Babá de Verão, Brisa, Carolina AG-576, Elisa, Lucy Brown, Marisa AG-216, Piracicaba 65, Regina 71, Tainá, Simpson, Vanessa and Verônica were evaluated. 'Regina 71' and 'Elisa' were only included on the dry season trial. The experimental design was a randomized block, with three replications. During the dry season, the cultivars Simpson, Lucy Brown and Regina 71 presented the largest average weights (373; 362 and 341 g, respectively) and commercial yields (49.8; 48.3 and 45.5 t/ha, respectively). In general, the cultivars with smooth leaves with or without head presented larger nematoid (Meloidogyne javanica) attack index, when compared to the curly type ones. In the rainy season trials, the cultivars Marisa AG-216, Verônica, Lucy Brown, Brisa, Tainá and Piracicaba-65 presented the greatest average weights and commercial yields. However, the obtained averages were very inferior to that verified in the trials of the dry period, varying from 164 to 198 g for average weight, and from 21.9 to 25.9 t/ha for commercial yield. Of those cultivars tested on the dry season, Regina 71 (butter head/less firm head) and Carolina (butter head) AG-576 stood out among the butterhead types, while Verônica, Marisa AG-216 (loose leaf/wavy and frilled leaves) were the best among the loose leaf types, obtaining good yield. 'Lucy Brown' stood out among the crisphead types.
Lactuca sativa L.; Meloidogyne javanica; yield; premature flowering resistance
