Water Restriction Affects Germination and Initial Sunflower Development

Sunflower is a crop of great economic interest both nationally and internationally, due to its use especially in oil production. However, factors such as water restriction are commonly found in growing areas and exert a negative influence on the productive performance of the crop, especially in critical periods, such as the germination and initial development of the seedlings. Thus, the objective of this study was to evaluate the germinate behavior of seeds of sunflower cultivars as a function of lower osmotic potentials. The experiment was installed in a completely randomized design, in a 3x5 factorial scheme, three sunflower cultivars (Charrua, Nussol and Olisiun 4) and five osmotic potentials (0, -0.2, -0.4, -0.8, -1.2 MPa) with 3 replicates. For the study, solutions of polyethylene glycol (PEG 6000) were repaired. Rolls of paper towels were moistened with the concentrations and later kept in a germination chamber at 25 °C, where they remained for ten days. First counts (4th day) and total counts (10th day) were performed, and the germination rate (%) was verified. In addition, in the last evaluation, aerial and root length, green mass and dry mass of seedlings were determined. Based on the results obtained it can be verified that in osmotic potential higher than -0.8 MPa, no germination occurred. Nussol germinated more in more negative concentrations, with a germination rate of 90%, differing from the cultivars Charrua and Olisiun 4, which, in larger potentials, reached only 30% of germination.