1991年我区推广用多效唑调节杂交水稻制种花期,获得显著成效。这种方法简单实用,效果明显,制种农户易于接受。实践证明,花期相差7天以内,都可采用多效唑调节花期。但在推广中也有不少教训。多效唑是一种生长抑制剂,用法不当不仅不能调节花期,还会引起负作用。因此,在使用过程中,必须严格遵守“三适”:一是施药要适时。实践证明,幼穗分化前四期,用药愈早效果愈好。用药过迟,不能起到调节花期的作用,对穗粒后期发育还有不利影响。所以要及早确定制 In 1991, our district popularized the use of paclobutrazol to regulate the flowering of hybrid rice seed production, and achieved remarkable results. This method is simple and practical, the effect is obvious, seed farmers easy to accept. Practice has proved that the flowering within a period of less than 7 days, can be used to regulate the flowering paclobutrazone. But there are many lessons in the promotion. Paclobutrazol is a growth inhibitor, inappropriate use of not only can not regulate flowering, but also cause a negative effect. Therefore, in the use of the process, we must strictly abide by “three appropriate ”: First, the drug should be timely. Practice has proved that the first four stages of panicle differentiation, the earlier the effect of medication the better. Medication too late, can not play the role of regulation of flowering, grain development late adverse effects. Therefore, we must determine the system as soon as possible