Effect of gibberellin and cytokinin regulators in overcoming dormancy of grass andropogon

Abstract

In the tropical forage grasses, the expression of dormancy is associated with physical and physiological causes present in freshly harvested seeds. The purpose of this work was to study the effects of vegetal growth regulators in the group of gibberellins and cytokines in overcoming dormancy of seeds of grass-andropogon. The experimental delimitation was completely randomized in factorial design (2 x 4) + 2, made by the combination of two vegetal growth regulators (gibberellins and cytokines) and four concentrations (75; 150; 225 and 300 mg L^-1a.i.), two evidences (with and without soaking in distilled water), with four replications of 50 seeds per treatment. The seeds were immersed in the solution for a period of 2-h. The variables analyzed were: physical purity, water content, weight of thousand seeds, germination, first germination, abnormal seedlings, dormant seeds, seedling emergence and index of speed emergence. The immersion of seeds of grass-andropogon provides increment in gibberellins, at a concentration of 225 mg L^-1, on germination and vigor. The cytokinin, the concentrations studied negatively affects seed quality.