Breaking seed dormancy in Hordeum spontaneum L

Breaking seed dormancy is an essential step towards germination improvement in Hordeum vulgare ssp. spontaneum. This study was conducted to evaluate the effects of physical, chemical, hormonal and stratification treatments on Hordeum spontaneum seed dormancy. In the current research two highly dormant genotypes of Hordeum spontaneum (TN1350 and TN951) were evaluated. To this purpose, 25 seeds in four replications were placed in 9 cm petri dishes containing filter paper saturated with distilled water (control), chemical or hormonal solutions. To induce the stratification treatments, seeds were kept in 35˚C (heat stratification) or 5˚C (cold stratification) for periods of 2, 4, 6 and 8 weeks. Results indicated that heat stratification increased germination significantly. Germination percentage of seeds under 35˚C treatments increased since the second week of treating and reached the maximum in the fourth week (47.5% in TN951 and 86.25% in TN1350). Results showed that GA3 in all used concentrations was the most effective hormone in inducing germination compaired to other used hormons in this study. The highest germination percentage in Hordeum spontaneum seeds was observed in 100 mg/l GA with increased germination percentage up to 68.75% in TN1350 and 31.25 in TN951. Results of this study revealed that seed dormancy in Hordeum spontaneum can be overcomed by GA3, and heat stratification. On the other hand, seed dormancy was apparently deeper in the genotype with darker seeds)TN951(which were also less affected by after ripening treatments.