Germinação de sementes de Milho adaptadas ao Cerrado sob estresse hídrico.

Abstract

The present word had as objective to evaluate the germination and growth of seedlings of wo maize cultivars under water deficit conditions induced with solutions of mannitol associated with doses of humic substtances.The experiments were conducted in the laboratory, and water stress conditions were induced by mannitol solution. The experiment was carried out in the Laboratory of Seed Analysis of the Federal University of Tocantins – UFT, in Gurupi, TO. Seeds of two cultivars were used: M274 and UFT Cerrado: and the product based on humic substances: Humix. For each cultivar the factorial experiment (5x3) installed in the completely randomized design was set up, with the treatments composed offive osmotic potentials.(0.0 control, -0.25, -0.5, -0.75 and -1. MPa). With three doses of Humix (0.0 control, 1.0 ml and 2.0 ml/ 100 seed). The percentage of germination, root length and aerial part, dry mass of seedlings and absolute growth rate were evaluated. The results were submitted to the F test by analysis of variance at 5% probability, and when the effect of the doses was significant the data were submitted to regression analysis. It is conclude that the biostimulant Humix did not have an expressive effect on the germination of the seed and that the reduction of the osmotic potential does not affect the germination and if, however, it affects the growth of the maize seedlings, as the osmotic potential becomes more negative. Key-words: Zea Mays. Mannitol. Osmotic potential. Hummic Substances.