辽宁省处于北方稻区,冷害发生频繁,约4—5年一遇。一般冷害年减产15-20%,重度冷害年达40%以上,其减产幅度之大,受害面积之广,是其它任何作物和自然灾害所难以比拟的。自1978年开始,通过各科研和生产单位的密切协作,采取多点自然分期播种和平行观测的方法,在省内各稻区进行了较为系统的低温冷害研究工作。三年来, Liaoning Province is in the northern rice area, chilling injury occurs frequently, about 4-5 years a case. The annual chilling injury rate is reduced by 15-20% and the severe chilling injury rate is more than 40%. The reduction rate is large and the affected area is wide. It is unmatched by any other crops and natural disasters. Since 1978, through close cooperation between various research institutes and production units, we have adopted more natural seeding and parallel observation methods to conduct systematic research on chilling damage in rice areas in the province. Three years ago,