目前,在农业生产上应用的連作晚稻品种,大都是原来作为单季晚稻或間作晚稻栽培的迟熟类型,生育期一般为180-200天。由于連作晚稻受到插秧季节和生育后期低溫的限制,本田生育期較短。为解决本田期短和这些品种生育期长的矛盾,广大农民,历来采用早播培育老秧的办法,来保証連作晚稻的安全生育,获得稳定的产量。但在培育老秧时,必須相应地減少秧田播种量,因而增大了秧田面积;并且老秧移栽后生长不旺,难于达到预期高产;加之老秧拔秧困难,不适机插,必然增加农忙季节劳力紧张,或延誤季节。这些都直接或間接地影响到連作晚稻产量及全年单位面积产量的提高。选用早中粳、中粳来代替晚稻作連晚栽培,就可有效地解决以上問題。一、早中粳、中粳作連作晚稻栽培的优越性近几年来,不少科研单位及生产部門都进行了早 At present, the continuous cropping late rice varieties used in agricultural production are mostly the late ripening types that were originally cultivated as single-cropped late rice or inter-cropping late rice. The growth period is generally 180-200 days. Due to continuous cropping season by late rice and low temperature during late growth limit, Honda shorter growth period. In order to solve the contradiction between the short period of Honda and the long growth period of these varieties, the majority of peasants have always adopted the method of early sowing old seedlings to ensure the safe birth of continuous cropping late rice and obtain stable output. However, when cultivating the old seedlings, the sowing amount must be reduced correspondingly, thus increasing the area of ​​the seedling; and the growth of the old seedlings is not good enough to achieve the expected high yield after being transplanted; besides, Busy season labor tension, or delay the season. These all directly or indirectly affect the production of continuous cropping and the increase of output per unit area throughout the year. The use of early middle japonica rice and medium japonica rice instead of late rice for later cultivation can effectively solve the above problems. First, the early middle and late japonica, middle and late japonica rice cultivation for the superiority of late rice In recent years, many scientific research units and production departments have carried out early