Effect of applying commercial gibberellins on seed germination of Chrysanthemum coronarium L.

Chrysanthemum coronarium L. is a very common species native to the province of Murcia, SE Spain, which flowers towards the end of winter. Although the plant produces a large number of seeds, the germination percentage tends to be very low. Since several studies have found that the application of gibberellic acid improves this percentage; the object of this work was to ascertain the effectiveness of commercial gibberellins on the germination percentage in C. coronarium. In the first experiment, the seeds were treated with novagib® (GA4/7 1%), clemencuaje® (GA3 1.6%), vip® (6-benzyladenine 1.9%+GA4/7 1.9%) or gibberellic acid (GA3 90%), at concentrations of 250, 500, 1,000, 1,500, 2,000, 2,500, 3,000 and 3,500 mg L-1. The results showed that novagib produced the highest germination percentage (24%). In a second experiment, binary combinations of these products were assayed but no synergistic effect was observed. A third experiment studied the effect of the gibberellins on intact and on naked seeds. The germination percentage in the naked seeds, whether or not treated with gibberellins, reached 90%. We conclude that the dormancy of C. coronarium seeds is regulated by coat imposed dormancy and not to the physiological processes regulated by gibberellins.