我省每年 3月和 4月上旬，一般都有多次寒潮侵袭，气温很低，增大了杂交稻父本育秧管理的难度，稍有不慎就会成片死苗甚至全田性毁灭，严重影响杂交稻制种的正常进行。　　一、死苗的一般症状　　1.青枯型 最初秧苗叶尖不挂露水，而后心叶突然萎蔫，卷成筒状，随后下叶很快失水 Every year in March and early April in our province, there are often many cold wave invasion, the temperature is very low, increasing the difficulty of hybrid rice parental seedling management, a little carelessness will become a piece of dead seedlings or even the entire field of destruction, Seriously affect the normal hybrid rice seed production. First, the general symptoms of dead seedlings 1. Wilt seedling tip of the first seed does not hang out dew, and then the heart leaves suddenly wilting, rolled into a tube, followed by rapid loss of the next leaf