八、抗性研究抗性研究是核桃科研的一个重要领域,就研究对象来说涉及面很广。可是二十年来国内外研究主要集中于核桃的抗寒性(抗冻性、抗霜性),而其它方面探索较少。这是因为核桃在某些地区栽培其抗寒性成为一个突出的问题,即使在适宜栽培区由于突然的降温导致核桃生长发育不良,甚至铸成巨大损失的事例也是司空见惯的。法国1965年一次严寒,使大量核桃树被冻坏,造成极大损失。在美国的东部和北部,因冻害问题解决不了,核桃一直不能大量发展起来。在苏联克里木北部,有的地区3—6年生的核桃树 Eight, resistance research Resistance research is an important area of ​​walnut research, research objects involved in a wide range. However, over the past two decades, the research at home and abroad has mainly focused on the cold resistance of the walnut (frost resistance and frost resistance), while less in other aspects. This is because walnut cultivation in some areas of its cold hardship has become a prominent problem, even in the appropriate cultivation area due to sudden cooling led walnut growth and development, and even cast a huge loss of the case is also commonplace. A cold in France in 1965, a large number of frozen walnut trees, causing great losses. In the eastern and northern parts of the United States, because of frost damage can not be solved, walnuts have not been able to develop in large numbers. In the northern part of the Soviet Union Crimea, some areas 3-6 years old walnut trees