国外引种是丰富品种资源,改良品种组成的重要途径,因收效快,用费少,历来受到各国的重视。五十年代以来,世界上栽培果树的主要国家美、日、法、英,意等国各种果树的发展相当迅速,其重要原因之一就是引用新品种,因而在产量,质量方面都获得很大提高。我国虽是多种果树原产地,种质资源十分丰富,但由于育种手段落后,生产品种更新慢。为了适应 Introducing foreign species is an important way to enrich variety resources and improve variety composition. Due to its fast efficiency and low cost, it has always been valued by all countries. Since the 1950s, the major countries in the world where fruit trees are cultivated in the United States, Japan, France, Britain, Italy and other countries have witnessed a rapid development of various fruit trees. One of the important reasons for this is the introduction of new varieties, and thus their yield and quality are very good Great to raise. Although our country is the origin of many kinds of fruit trees, germplasm resources are very rich, but due to the backward breeding methods, the production of new varieties slowly. In order to adapt