The objective of the present study was to investigate effective methods in breaking the seed dormancy for annual medics species. Three experiments were conducted to evaluate seed germination of annual medics including Medicago radiata, Medicago polymorpha and Medicago rigidula under different prechilling, gibberellic acid and potassium nitrate concentrations and sulfuric acid concentrations in 5 and 10 min of applying time. The result showed that all methods broke seed dormancy and exhibited seed germination of annual medics, but some cases were different in cultivars. The most effective and practical method for seed dormancy breaking in M. polymorpha and rigidula was 96% sulfuric acid application for 10 min. The main advantages of this method are speed, ease of use and unaltered physical condition of the seeds following treatment and cheap. The concentration of 750 ppm gibberellic acid with prechilling in 4°C was the most effective and practical method in breaking hard seed dormancy of M. radiata.
Hamid Reza Balouchi and Seyed Ali Mohammad Modarres Sanavy , 2006. Effect of Gibberellic Acid, Prechilling, Sulfuric Acid and Potassium Nitrate on Seed Germination and Dormancy of Annual Medics. Pakistan Journal of Biological Sciences, 9: 2875-2880.