COMO A ESPUMA FENÓLICA AFETA O CRESCIMENTO DE MUDAS DE ALFACE CRESPA, INCLUINDO TEMPOS DE BERÇÁRIO E SUBSTRATOS

Abstract

The curly lettuce corresponds to a large share of national sales. And this is related to its crunchiness. However, research on the production of seedlings needs to be updated according to the technologies available in the production of seedlings, mainly for hydroponic systems. Little information is available when considering the comparison between different substrates for accommodation of lettuce seeds, as well as nursery times. The objective was to evaluate the influence of different nursery times on the development of crisp lettuce seedlings, under two growth media: conventional styrofoam or phenolic foam seedlings. Sowing was carried out in Styrofoam trays, including substrate for seedling growth, or phenolic foam. The treatments were seedlings 15 days after sowing (DAS) in the nursery, 20 DAS, 25 DAS and, finally, 30 DAS in the nursery. The other factor, growth media, had substrate levels (in Styrofoam trays) or phenolic foam. A DIC following a 4 x 2 factorial arrangement was programmed, with 8 treatments and 100 repetitions for each experimental unit. Seedling development and quality parameters were quantified, such as seedling height (cm), fresh weight (g) and dry weight (g) of curly lettuce seedlings. Larger seedlings were observed at 25 DAS (T3) for those maintained with substrate and at 30 DAS for those maintained in phenolic foam, which proves that the type of seedling growth medium interfered with the height of the seedlings. The curly lettuce seedlings were higher in height in the foam compared to the substrate, only at 30 DAS (T4). The production of fresh pasta was also influenced by the growth medium, with the exception of T2. And, finally, there was no significant difference for the dry mass of lettuce seedlings depending on the type of growth medium. Seedlings of curly lettuce, with longer nursery time, provided seedlings with higher growth values than those that follow the standard adopted in Brazil: Styrofoam trays and substrate with 15 days of transplanting. Phenolic foam ´may become an important growth medium for the production of curly lettuce seedlings.