Effect of Gibberellin and Cytokinin on improvement of germination traits and seed vigor of deteriorated corn cultivars (Zea mays L.)

The present research was conducted to determine the effect of Cytokinin and Gibberellin hormones on the improvement of germination traits of maize cultivars with different vigor. The experiment was conducted in the seed laboratory of the Agronomy and Plant Breeding Department of the Faculty of Agronomy and Animal Science of University of Tehran in 2015. The maize cultivars used included Hybrid Single Cross 704 cultivar and Hybrid Single Cross 260 Cultivar. Standard germination test was completely randomized performed to determine the voguers of two cultivars of corn. 704 cultivar showed higher germination indices than 260 cultivar. The seeds were then investigated in the form of factorial in a completely randomly design in a completely randomized design with four replications in order to create different vigorous under the pre-mature aging test at 5, 10 and 15 days and after the pre mature aging test of the effect of different concentrations of Cytokinin and Gibberellin hormone on decayed seeds of corn cultivars. In all experiments, the traits of germination percentage and rate, root length, shoot length, root fresh weight, stem fresh weight, root dry weight and shoot dry weight were measured. The obtained results showed that aging or seed deterioration, causes reduction in germination percentage and rate, root length, root fresh weight, stem fresh weight, root dry weight and shoot dry weight. Under pre mature aging treatments, the difference was significant between cultivars. In 704 cultivar, traits measured under pre mature aging treatments showed a lower reduction than 260 cultivar. The treatment of decayed seeds with Gibberellin and Cytokinin hormones improved the measured traits. The effect of higher concentrations of hormone in long-term aging treatments was very significant. Increasing the concentration of hormones from 50 micromoles to 150 micromoles improved the measured traits.