Hawthorn, is one of the crucial tolerant seedling rootstocks to iron deficiency chlorosis for quince and pear trees in calcareous soils. In this investigation, owing to double seed dormancy, low percentage of seed germination and producing seedling rootstocks, two factorial experiments in a completely randomized design with three replications were conducted to dominate seed dormancy in hawthorn. In the first experiment, researched the effect of seed scarification with concentrated sulfuric acid (98%) in three time period including 0, 1.5 and 3 hours and four warm-cold temperature treatment (3 months at 20 °C and then 3 months at 4 °C; 3 months at 30 °C and 3 months at 4 °C; 3 months at 20 °C and then 4.5 months at 4 °C; 3 months at 30 °C and then 4.5 months at 4 °C) in two hawthorn species namely Crataegus meyeri and C.atrosanguinea . In the Second one, the germination of seed embryos in C.atrosanguinea were evaluated under different concentrations of potassium nitrate (0, 5000 and 10000 ppm) and gibberellic acid (0, 100 and 200 mg per liter) in vitro. The germination percent (GP), mean daily germination (MDG), rate of germination (T50), mean time needed for germination (MGT), length of hypocotyl and epicotyl, seed germination (GI) and seed vigor indices (SVI) were evaluated and measured. The results of first experiment showed that the scarification time and temperature treatments, have significant effects in increasing GP, MDG, length of hypocotyl and epicotyl, GI and SVI, and reduced the T50 and MGT average compared to control in both species. The results of the second experiment indicated that the applications of 100 mg per liter gibberellic acid, and 5000 mg per liter of potassium nitrate significantly increased GP, MDG, GI, SVI and decreased T50 compared to the control. On the whole, the results imparted the significant increasing of hypocotyl and epicotyl length by gibberellic acid at 200 mg per liter and potassium nitrate at and 5000 mg per liter as compared to control, and notably effect of cold on the lessening of MGT. Keywords : temperature treatment, Gibberellic acid, Germination, Dormancy, Scarification, Crataegus, Potassium nitrate