Rendimento de cultivares de alface do grupo Americana, em diferentes épocas e sistemas de cultivo, na condição edafoclimática do município de Presidente Figueiredo - AM

Abstract

The Lettuce ( Lactuca sativa L.) is the most sold and leafy vegetables consumed in natura from Brazil. The iceberg lettuce, also known popularly as lettuce, cabbage, stands out among the other varieties for its crunchy texture, excellent palatability, increased shelf-life and resistance to dehydration caused by heat. This study aimed to characterize, evaluate and select lettuce cultivars of the American group in terms of productive per formance. Two experiments were conducted in Latossolo Yellow in a rural area of the Presidente Figueiredo - AM, in periods of 08/04, 15/06 and 08/09, 10/11 of 2011, corresponding to the times of occurrences of rainy and dry season in Central Amazon. In the rainy season the experiment was conducted with 20 cultivars common in beds and borders protected with plastic wrap double sided (black/silver). During the dry season, were used 19 varieties, grown in beds and borders with common coverage of sawdust (SM). In both schemes were adopted factorial experiments and comparison of means test ScottK-nott. The results on the qualitative and quantitative characters evaluated at different planting dates permit us to dsitinguish cultivars with good productive performance standards associated with quality and morphological stability. In the rainy season, plants grown in beds covered with plastic wrap double sided were bette r in health, height, number of leaves, head daimeter and yield of commercial fresh matter than those grown in soil without the use of mulching. In the dry season, thcueltivation of plants in plots with the use of SM as a cover of the beds, was significantly more efficient compared to those grown in conventional beds, features, health, commercial fresh mass, number of leaves and stem length. However, in both lctuure systems used for production of lettuce American group at different times of year cultivars Gloriousa Havassu, Healtmaster, Kaiser and Lucy Bronw, which were better adapted to climate conditions in the municipality of Presidente Figueiredo and are suitable for cultivation to farmers in the region.