A REVIEW OF BREAKING SEED DORMANCY IN HAWTHORNS (Crataegusspp.)

Propagation of hawthorns (Crataegusspp.) is difficult, and vegetative methods are not responsive in a sufficient manner. So, seed propagation is prevalently used to propagate hawthorns. However, hard endocarp and embryo dormancy restrict the germination of hawthorns. To overcome these restrictions, many treatments have been tested in the researches. Some of them were magnificent and others ineffective. It has been resolved that warm and cold stratification are the best for breaking dormancy in seeds of hawthorns. Thus far, no substitution has been found for warm and cold stratification treatment to release the seeds of hawthorns from dormancy, from the conventional point of view. Besides, combination with other factors may reduce the period and temperature degrees of warm and cold stratification, for instance, species, eliminating endocarp, treatment with growth regulators, and chemical scarification. In this review, the results of methods will be referred to that used in the studies to break seed dormancy in hawthorns.