Current status of exploitation and application of Hawthorn genus (Crataegus spp.) resources in China.

Crataegus spp. plants are one of the most important germplasm resources of fruit trees in China. In recent years, a lot of Hawthorn germplasm waterials were collected from all over the country, and preserved in conservation nurseries. These germplasm resources were evaluated and identified on the basis of morphological and agronomical characteristics, and the Description and Data Standard for Hawthorn (Crataegus spp.) have been worked out. Many physio-biochemical and molecular techniques, viz., peroxidase isozyme zymogram, RAPD, ISSR, cpDNA PCR-RFLP and cpSSR, etc., have been used to classify them and to study the genetic diversity for innovative application of Hawthorn germplasm resources. Future studies must be concentrated upon use of modern molecular marker techniques to study and to understand the phyletic evolution, classification, genetic diversities and polymorphism amongst Hawthorn germplasm resources, which will help in constructing the genetic database of core germplasm and will facilitate the genetic engineering researches. Further, suggestions have been given to strengthen the polyploidy breeding and the breeding of Hawthorn varieties with special reference to its medical role in health care, wide ecological adaptability, strong fertility, fine quality in order to make use of this important plant species.