Effect of environment and agricultural variability on seedling formation and production of lettuce (<em>Lactuca sativa</em> L. cv. Elisa)

Abstract

Evaluation of effects of environment and agricultural variations on the production phase of lettuce seedlings, Lactuca sativa cv. Elisa (Asteraceae) is provided. Seedlings were cultivated on insulating trays, from August to October 1997, in Maringá PR Brazil. Complete randomized block design with four replications was used during pre - and post-transplantation phases to evaluate treatment controls, transplantation delay, roots without above-ground pruning, high temperature during germination phase, water deficiency, excessive watering, substratum salination, aerial fertilization, direct sunshine, high temperature in growing phase and shade. While growth patterns of seedlings in transplantation were evaluated, productivity parameters were also assessed during harvest. Highest production of dry matter of aerial part and root was obtained from delay in transplantation. Productivity of commercial plants varied from 33.1 to 38.4 t/ha, although it was not significantly affected by treatments applied before transplantation