Efeito do ácido giberélico sobre a germinação e vigor em sementes de alfafa

Abstract

Alfalfa (Medicago sativa L.) is one of the most important forage crops, being widely cultivated in the Brazilian territory, and in several countries, because the crop has good adaptability to different cultivation environments. Its seed, because it has a very hard coat, causes the germination to be compromised, either by delay or by not occurring. Thus, the objective of the present study was to evaluate the germination and vigor of alfalfa seeds submitted to different concentrations of gibberellic acid. The experiment was conducted at the Plant Physiology Laboratory and the Seed Laboratory of the Universidade Federal da Fronteira Sul - Campus Cerro Largo. We used the Completely Randomized Design with four repetitions and six treatments, in which the concentrations of gibberellic acid, being 0, 25, 50, 75, 100 and 200 ppm, with 25 seeds in each repetition. The percentage of germination, the germination speed test (IVG), mean length of aerial part (CMPA) and mean length of root part (CMPR) were evaluated. The results obtained were subjected to analysis of variance (ANOVA), using the SISVAR program, and then submitted to regression analysis. With the results obtained, it was observed that alfalfa seeds, with the application of gibberellic acid, had a reduction in the percentage of germination as increased the concentration. In relation to IVG, as the doses in the treatments increased, the index decreased. The same was observed for the average length of the aerial and radicular part, there was a decrease in the size of the seedlings. Thus, it was observed that no satisfactory results were found in the treatment of alfalfa seeds with gibberellic acid.