Seed dormancy breaking in Crataegus pedicellata

The effects of stratification and scarification on seed dormancy breaking were compared in scarlet hawthorn (Crataegus pedicellata Sarg. = C. coccinea L). Ripe fruits were collected (in October) and the extracted nutlets were cleaned, and dried to a moisture content of 9-12%. Seed dormancy in this species was broken most effectively by warm-followed-by-cold stratification of nutlets, in a substrate or without any substrate, as well as at 15 similar to 25 degrees or 20 similar to 30 degrees C, i.e. with a cyclically alternating warm stage (16+8 hrs or 24+24 hrs/cycle) lasting 16-20 weeks, followed by the cold stage at 3 degrees C lasting ca. 20 weeks, i.e. till the appearance of the first germinating seeds. After stratification, emergence rate is equally high (ca 76%) at cyclically alternating temperatures of 3 similar to 15 degrees C or 3 similar to 20 degrees C (16+8 hrs). Chemical scarification of nutlets in 96% sulphuric acid for 2 hrs, followed by warm-cold stratification at 20 similar to 30 degrees/3 degrees C, with a short, 4-weeks warm stage, also ensures a high emergence rate (85-93%). Seed desiccation (in nutlets) slowly to moisture content of 12-14%, after stratification in a substrate or scarification does not reduce the seedling emergence of seeds. Emergence decreased when seeds were desiccated after stratification without any substrate. Results provide new methods of breaking of dormancy and high germination and emergence of hard-coated Crataegus seeds in controlled conditions.