Three distinct trials were carried out at Três Pontas city in Minas Gerais Satate, Brazil, from December 2002 to February 2003 with the objective of evaluating the influence of doses of copper on the yield of crisphead lettuce (Lactuca sativa L.). The experimental design was in randomized complete blocks with five treatments, being one control and four doses of copper ( 0.15; 0.30; 0.45 and 0.60 l/ha) and three application times applied via foliar (14, 21 and 28 days after transplanting). Each application time was considered one trial. The highest plant commercial fresh mass was obtained at the doses of 0.35 l/ha of cooper, with an increment of 20.5% of increase in yield, comparatively to the control. The application at 21 and 28 days after transplanting showed the higlest stem length with 5.7 and 6.1 cm in length, respectively. The dose of copper (0.45 l/ha) promoted the highest circumference of the commercial head. Regarding the sanity of the leaves a quadratic effect was verified, in which, the dose of copper (0.41 l/ha) showed the best sanity of the external leaves, when applied to the 21 and 28 days. No significant effect among the treatments for total fresh matter was observed.
Lactuca sativa; micronutrient; fresh mass; postharvest quality; sanity
