Production of sweet potato seedlings in protected environment with the application of Ascophyllum nodosum extract

<p></p><p>ABSTRACT The sweet potato is a crop adapted to tropical climates and has low tolerance to mild temperatures, which reduces the time available for cultivation in southern Brazil. Therefore, techniques aimed at process optimization, such as the production of seedlings in trays in protected environment, together with the application of biostimulants, becomes an efficient alternative to reduce the crop cycle. The objective was to evaluate the use of Ascophyllum nodosum seaweed extract in the production of sweet potato seedlings in trays under greenhouse conditions. We used the randomized block design with split plot with five extract concentrations (0.0%, 0.5%, 1.0%, 1.5% and 2.0%) and three parts of the branch of sweet potato plants (basal, middle and apical) and 9 repetitions. We evaluated aspects of vegetative propagation and fresh and dry weight of the plant organs. Positive results were observed for all characteristics when used in the apical portion of the branch, regardless of the concentration of algae extract applied. With respect to the concentrations used, practically all the features corresponded to the increase in doses, regardless of the portion of the branch used. It is attributed to the presence of cytokinins and auxins and other chemicals present in the A. nodosum extract and in the structure of the plant, the beneficial effects observed. The best results were found on the apical portion, combined with the concentration of 1% of the product. The kelp extract optimized the formation of sweet potato seedlings in trays, contributing to the increase of force and consequent precocity of them.</p><p></p>