Progress of collection, conservation and innovative utilization of hawthorn resources in the National Hawthorn Germplasm Repository (Shenyang)

China is one of the origin center of Crataegus plants, and the hawthorn germplasm resources in China are very rich. Crataegus pinnatifida Bge. var. major N. E. Br. is a kind of unique temperate fruit tree with plenty of cultivars and has been cultivated for a long time (more than 700 years). It is essential for China’s fruit tree industry, and can provide useful materials for hawthorn breeding and the development of hawthorn industry. The current national cultivation area of hawthorn is approximately 95 000 hm2 , with an output of about 1 million tons. Hawthorn fruits are primarily used as raw materials for processing rather than fresh consumption. They can be used for production of fruit wine, juice, fruit leather (e.g., hawthorn rolls), dried slices, and candied haws (Bingtanghulu) and other processed foods. Moreover, hawthorn is also can be used for manufacture of medicine. The fruit is rich in vitamin C and bioactive compounds such as flavonoids, organic acids, triterpenoids, and sterols which are beneficial for human health. The national hawthorn germplasm repository (Shenyang) was firstly built in 1982 and located on the campus of Shenyang Agricultural University. It serves as the primary unit for the preservation of hawthorn germplasm resources in China. Till the end of December 2024, the national hawthorn germplasm repository (Shenyang) has collected, preserved and catalogued 420 accessions of hawthorn germplasm resources, including 19 species of Crataegus and 13 accessions of foreign hawthorn germplasm resources. Many researches have been carried out in the National Hawthorn Germplasm Repository (Shenyang) including the analysis of the hawthorn genome, the evolution analysis of Crataegus bretschneideri C. K. Schneid., and the molecular marker development. We associated with the researchers of other unit, provided a de novo chromosome-level genome sequence of the hawthorn cultivar Qiu Jinxing. The new high-quality reference genome provided a useful resource for the horticultural improvement of hawthorn. The germplasm evaluation works included developing SSR-based molecular IDs for hawthorn varieties, analyzing color-anthocyanin relationships in 51 accessions and decoding the flavonoid profiles in black hawthorn fruits. Using soft- fleshed accession Ruanrou 3 and conventional cultivar Qiujinxing as experimental materials, we demonstrated that fruit softening in hawthorn might be associated with the activities of polygalacturonase (PG), pectin methylesterase (PME) and cellulase (Cx). With the utilization about the hawthorn resources, the National Hawthorn Germplasm Repository (Shenyang) has played an important role in the rural poverty alleviation and sustainable industrial development. In recent years, we provided over 500 samples of germplasm resources and information services to research institutions, universities, and enterprises across China, with a high level of user satisfaction. In the future, the collection and preservation of hawthorn germplasm resources will be further enhanced to facilitate their systematic, evaluation and utilization researches. The efforts will focus on optimizing conservation techniques and establishing efficient sharing systerm. Additionally, biotechnological approaches will be explored for germplasm innovation, alongside the training of specialized research talents and development of technical teams. This review would offer useful information for the effective utilization of China’s hawthorn germplasm resources.