辽宁是我国苹果生产基地之一,产量达13.6亿斤,次于山东而居全国第二位。辽宁栽培苹果的历史悠久,生长季气候条件适宜,产量和质量比较稳定,发展苹果生产具有很大潜力。但冬季不良的气候条件常给苹果树造成不同程度的冻害,因而限制了大苹果的栽培北限并明显地影响品种的地理分布。继1952～1953年、1956～1957年、1976～1977年之后,1980～1981年辽宁省出现了解放以来第四次大冻害。据不完全统计,这次冻害共冻死苹果树50万株以上,减产达几千万斤之多,给苹果生产带来很大危害。这次冻害主要发生在辽宁的东部,即营口、鞍山、辽阳、本溪、丹东、沈阳、抚顺等地区,其中以盖县、营口、海城、辽阳、本溪、宽甸、凤城等县最严重。冻害级别≥3级 Liaoning is one of the apple production bases in China with a yield of 1.36 billion kilograms, ranking second in the country for Shandong. Liaoning has a long history of cultivated apples, suitable climatic conditions during the growing season, relatively stable yield and quality, and great potential for developing apple production. However, poor winter climatic conditions often cause different degrees of frost damage to apple trees, thus limiting the northern limit of big apple cultivation and obviously affecting the geographical distribution of varieties. Following 1952 ~ 1953, 1956 ~ 1957, 1976 ~ 1977, Liaoning Province from 1980 to 1981 appeared the fourth big freeze since liberation. According to incomplete statistics, the frostbite has frozen more than 500,000 apple trees and cut down the output by tens of thousands of kilos, bringing great harm to apple production. The freeze occurred mainly in the eastern part of Liaoning Province, namely Yingkou, Anshan, Liaoyang, Benxi, Dandong, Shenyang, Fushun and other areas, including Gaixian, Yingkou, Haicheng, Liaoyang, Benxi, Kuandian, Fengcheng counties the most serious . Frost damage level ≥ 3 level