以陇棉3号为材料，观察了新型化学打顶剂不同打顶时间和剂量对棉花农艺性状、新生节间长度、新生果枝长度及产量和品质的影响。结果表明，该新型化学打顶剂能够降低棉花株高，较人工打顶能够增加果枝数、降低上部果枝长，增加果节数，并能有效抑制新生节间和新生果枝长度，对单株铃数、铃重、衣分和绒长无明显影响。与人工打顶相比，同期喷施750 mL/hm2该化学打顶剂，籽棉产量无显著差异，可以起到替代人工打顶的作用。

With a cotton cultivar Longmian 3 as test material， the effects of different topping time and dose of a new chemical topping agent on agronomic traits， length of new internodes and branches， yield and quality were studied. The results show that compared with manual topping the new chemical topping agent can reduce the height of plant， increase the number of fruit branches， reduce the length of upper branches， increase the number of fruit nodes， and inhibit the length of newborn internodes and new branches effectively. It had no significant influences on boll number， boll weight， ginning outturn and fuzz length. Compared with manual topping treatment， spaying the chemical topping agent of 750 mL/hm2 has no significant difference in the cotton yield， and can replace artificial topping.

S562

国家重点研发计划专项(2017YFD0101603)；国家重点研发计划(2017YFD0201905)；甘肃省科技重大专项(17ZD2NA016-6)；甘肃省农业科学院科技支撑项目(2016GAAS01)。