中文摘要：

核桃是世界范围内的重要果树，无论面积和产量在各类干果中居首位。种质资源是核桃品种选育的基础，对国内外核桃种质资源研究工作进行了全面综述，包括国内外种质资源研究现状、分类和利用现状、品种类型适应性研究等方面，并对美国国家种质资源圃收集及利用情况进行了介绍。提出在今后的核桃种质资源研究工作中，应充分发挥我国资源丰富的优势．加强和利用不同特异类型及生物技术开展核桃的种质资源研究。

英文摘要：

Walnut has been widely cultivated for nut fruit production in the world ,both cultivation areas and yield are premier in the world nuts production. Germplasm is the foundation for walnut breeding, the status of germplasm worldwide collection and utilization, the status of the walnut germplasm repository in the United States, the adaptability of the different walnut groups to the ecological conditions, the existing commercial walnut cultivars and selections grown in the world, the cuhivars having high resistance to diseases and the newly bred euhivars and selections, and the focus of the breeding programs in the world are reviewed and discussed in this article.