THIRTY YEARS OF BREEDING WALNUT IN CHINA

Previously walnuts were a major crop and industry in China to the extent that China was the leading country for walnut production and exports to the world. In an effort to regain that status in recent years, a lot of work has been done on walnut variety selection and breeding. Germplasm of walnut was collected from around the world and maintained in China. The national repository for walnut germplasm was established in Shandong province, where a wide range of walnut germplasm is preserved. Further study has been conducted on the classification and evaluation of the germplasm held in the repository. A breeding program has been established based on the germplasm of interest. Optimal cultivars, possessing traits of precocity, high production, good quality and resistance to diseases and pests, have been selected as well as rootstocks with tolerance and resistance. The process has involved crossing, selection from seedlings and introductions from around the world. The outputs of these breeding efforts have greatly promoted the Chinese walnut industry.