Progress of collection, conservation and innovative utilization of chestnut resources in the National Walnut and Chestnut Germplasm Repository (Tai’an)

Chestnut, a deciduous tree of the genus Castanea in the Fagaceae family, is native to China and has a cultivation history of at least 2500 years. It is an important woody food crop and a long-lived economic fruit tree that can be planted once and harvested for a hundred years. Chestnuts are widely cultivated in China, with a total area of nearly 1.9 million ha and a total output of over 2 million tons. Both the cultivation area and output rank top in the world. As the original home of Chinese chestnuts, China has rich germplasm resources, diverse seedling variations, and great potential for selection. Continuously strengthening the collection and preservation of chestnut germplasm resources will help promote the innovative development and sustainable utilization of Castanea resources. In response to China’s rich chestnut resources, from the mid-1950s to the 1960s, China conducted its first nationwide survey of chestnut germplasm resources, collecting and organizing about 300 local varieties and over 50 superior introduced germplasms. A chestnut germplasm resource collection was established at the Nanjing Botanical Garden of the Chinese Academy of Sciences. Subsequently, many research institutions established their own resource gardens. The Chinese chestnut germplasm resource collection was established in 1980 based on the Original Resources Garden of the Shandong Institute of Pomology. In 1989, after expert review by the Ministry of Agriculture (now the Ministry of Agriculture and Rural Affairs), the National Chestnut and Walnut Germplasm Resource Collction in Tai’an, built by the Shandong Institute of Pomology, was officially approved as a national-level germplasm resource collection and finacially supported by the key science and technology program of the national Seventh Five-Year Plan. Currently, the National Walnut and Chestnut Germplasm Repository (Tai’an) is the main preservation unit for chestnut germplasm resources in China and is also the world’s largest, most complete, and most standardized chestnut germplasm resource collection. 504 accesions of chestnut germplasm resources have been collected and preserved by December, 2024, and many, special germplasms have been selected and such as Red Chestnut, Weeping Chestnut, Flowerless Chestnut, Thornless Chestnut, and Short Branch Chestnut, and more than ten multiple high- quality chestnut varieties have been bred such as Songjia Zao, Shifeng, Huafeng, Yanhong, Yanfeng, Hongli No.1, Hongli No. 2, Jiujia Zong, Chushu Hong, and Yimeng Short Branch. The basic researches on the origin and evolution of chestnuts, molecular marker-assisted breeding, quality improvement, and disease resistance have contributed to the adjustment of chestnut variety structure and industrial upgrading, playing an important role in rural revitalization and sustainable industrial development. Currently, after multiple resource surveys, the quantity and quality of chestnut germplasm resources have significantly improved, but there are still some deficiencies. For example, the collection range of the germplasm resources is not comprehensive, the preservation mainly relies on seedling preservation and seed preservation, the preservation technology level needs to improve, the utilization of resources is not sufficient, and the data information sharing mechanism is not perfect. In the future, studies on the molecular biology, cell biology and developmental biology of chestnuts, and active functional components of chestnuts and the development of new deeply processed products should be strengthened to satisfy the needs of breeding and industry.