在“农业学大寨”运动的推动下,我国耕作制度发生了很大的变化。双季稻、三熟制(早稻、后季稻和麦子)的面积不断扩大,粮食产量也随之不断上升。在长江以南地区早稻是比较稳产、高产的一熟。但是,与后季稻相比,它的空秕率比较高,不少品种空秕率达30％左右,然而,同样的品种,用作后季稻种植时,空秕率就减少到15％左右。这是为什么呢?其中一个重要原因,就是早稻在开花结实时期,往往容易受到较高温度的伤害。这个问题由来已久,在由二熟变为 Driven by the “Agriculture Studies in Dazhai” movement, great changes have taken place in our farming system. The area of ​​double cropping rice, third cropping (early rice, later season paddy and wheat) is continuously expanding, and the grain yield will also continue to rise. Early rice in the area south of the Yangtze River is a relatively stable, high yield of a cooked. However, compared with the latter season rice, it has a relatively high vacancy rate of about 30% in many varieties. However, when the same variety is used as a planted rice in later rice, the rate of vacancy is reduced to 15% about. Why is this? One of the important reasons for this is that early rice tends to be exposed to higher temperatures during its flowering period. This problem has a long history, changed from two ripening