Breaking of seed dormancy, germination and seedling emergence of the common hawthorn (Crataegus monogyna Jacq.)

The most advantageous time for collecting fruits of the common hawthorn (Crataegus monogyna Jacq.) falls on October, when they are fully ripe. The stones extracted from the fruits must be dried at room temperature to the moisture content of about 10%. The dormancy of the common hawthorn seeds can be overcome by their stratification in a moist medium in one of the three thermal regimes: - 25°/3°C (16 weeks at 25°C followed by 15-18 weeks at 3°C, i.e. to the time when the first seedlings start to appear) - 20~30°/3°C (16 weeks at 20~30°C (16+8 hrs/day) followed by 15-18 weeks at 3°C, i.e. to the time when first seedlings start to appear) - 20~30°/3°C (16 weeks at 20~30°C (24+24 hrs) followed by 15-18 weeks at 3°C, i.e. to the time when first seedlings start to appear) Having been stratified, the seeds germinate vigorously (in 3-5 weeks) and at a high percentage at temperatures of 3~10°, 3~15°, 3~20° and 3~25°C, (16+8 hrs/day) and the seedlings emerge at 3~20°C (16+8 hrs/day) in 4-6 weeks. Storage for one year at -3°C in the case of the seeds dried after harvest to the moisture content of 10% does not reduce their germination capacity. Stones scarification in concentrated sulphuric acid for 120 minutes followed by stratification at 3°C has an adverse effect on seed emergence at the temperature 3~20°C (16+8 hrs/day). It is recommended that stratified seeds should be sown into the still cool soil at the end of March or the beginning of April, as the increased temperature induces the secondary dormancy in seeds.