The use of a compost activator to overcome seed dormancy in Rosa canina

Seeds of Rosa canina possess a complex dormancy mechanism which normally requires protracted periods of natural stratification before germination is possible. As an alternative pretreatment it is shown that the compost activator, Garotta, is able to break seed dormancy when incorporated into the stratification mixture. In the absence of Garotta 0.5% of seeds germinated after a stratification treatment of 13 weeks at 20°C + 12 weeks at 4°C. In contrast, when the compost activator was used germination rates increased to between 39.0% and 50.25% depending on the level of Garotta added. Germination was also more rapid and more uniform in the Garotta treated seeds. It would appear from the germination results obtained when alternating temperatures (5°C/25°C) were used that increased germination would have resulted from a longer period of cold treatment. Future experiments in which the moisture content is reduced during the cold stratification period in an effort to delay radicle emergence, during pre-treatment, are suggested.