Abstract: The effects of different topping agents［Tuyouta（flumetralin），Great Wall Brothers（mepiquat chloride）］and spraying time（July 5，July 10，July 15）on agronomic traits，yield and quality of cotton were studied with five main cotton varieties in southern Xinjiang，so as to determine the types and spraying time of topping agents suitable for southern Xinjiang cotton area，and provide theoretical basis for the promotion and application of chemical topping agents in cotton area of southern Xinjiang.The results showed that compared with 1 d after spraying，the plant height of cotton increased by 8.9% and 12.9%，number of fruit branches increased by 27.0% and 22.7%，and number of bolls per plant increased by 2.2 times and 2.8 times，respectively，at 21 d after spraying Tuyouta and Great Wall Brothers on July 5；The plant height of cotton increased by 11.0% and 6.3%，number of fruit branches increased by 8.9% and 12.3%，and number of bolls per plant increased by 3.7 times and 5.4 times，respectively，at 21 d after spraying topping agent on July 10；The plant height of cotton increased by 9.8% and 7.3% respectively，number of fruit branches increased by 12.4% and 22.3% respectively，and number of bolls per plant increased by 2.2 times and 1.4 times respectively，at 21 d after spraying topping agent on July 15.Compared with the treatment spraying Great Wall Brothers，the boll number，lint percentage，seed cotton yield，lint yield，uniformity and breaking strength of the treatment spraying Tuyouta on July 5 increased by 7.0%，2.6%，3.4%，0.40% and 0.7%，respectively；The boll number，seed cotton yield，lint yield，fiber length，uniformity and breaking strength of the treatment spraying Tuyouta on July 10 reduced by 3.11%，10.2%，4.7%，4.0%，0.67% and 3.4%，espectively；The boll number，lint percentage，seed cotton yield，lint yield，fiber length，uniformity and breaking strength of the treatment spraying Tuyouta on July 15 increased by 13.7%，0.4%，9.0%，9.7%，6.8%，0.19%and 4.3%，respectively.By comparing different spraying time，as a whole，it was found that the control effect of spraying topping agens on July 10 on plant height was the best，and the number of bolls per plant，number of bolls，seed cotton yield，lint yield and Micronaire were the highest. The results of cluster analysis showed that spraying Tuyouta was better than spraying Great Wall Brothers，and the best spraying effect was on July 10，followed by July 5.In summary，in the cotton area of southern Xinjiang，spraying topping agents on July 10 can effectively control the plant height of cotton，increase the number of bolls per plant，optimize the spatial structure of cotton，and enhance yield and quality of cotton，especially Tuyouta.

Key words: Cotton, Topping agent, Spraying time, Agronomic traits, Yield, Quality, Southern Xinjiang

摘要： 以南疆棉区主栽的5个棉花品种为材料，研究不同打顶剂［土优塔（氟节胺类）、长城兄弟（缩节胺类）］及喷施时间（7月5日、7月10日、7月15日）对棉花农艺性状、产量及品质的影响，以期确定适合南疆棉区的打顶剂种类和喷施时间，为南疆棉区化学打顶剂的推广和应用提供理论依据。结果表明，与喷施后1 d相比，7月5日喷施土优塔和长城兄弟后21 d，棉花株高分别增加8.9%和12.9%，果枝台数分别增加27.0%和22.7%，单株结铃数分别增加2.2倍和2.8倍；7月10日喷施打顶剂后21 d，棉花株高分别增加11.0%和6.3%，果枝台数分别增加8.9%和12.3%，单株结铃数分别增加3.7倍和5.4倍；7月15日喷施打顶剂后21 d，棉花株高分别增加9.8%和7.3%，果枝台数分别增加12.4%和22.3%，单株结铃数分别增加2.2倍和1.4倍。与喷施长城兄弟处理相比，7月5日喷施土优塔处理棉花铃数、衣分、籽棉产量、皮棉产量、整齐度和断裂比强度分别提高7.0%、2.6%、3.4%、6.3%、0.40%和0.7%；7月10日喷施土优塔处理棉花铃数、籽棉产量、皮棉产量、纤维长度、整齐度和断裂比强度分别降低3.11%、10.2%、4.7%、4.0%、0.67%和3.4%；7月15日喷施土优塔处理棉花铃数、衣分、籽棉产量、皮棉产量、纤维长度、整齐度和断裂比强度分别提高13.7%、0.4%、9.0%、9.7%、6.8%、0.19%和4.3%。不同喷施时间之间比较发现，总体上以7月10日喷施打顶剂对株高的控制效果最好，且单株结铃数、铃数、籽棉产量、皮棉产量及马克隆值最高。聚类分析结果表明，喷施土优塔优于喷施长城兄弟，且7月10日喷施效果最好，其次是7月5日。综上，在南疆棉区，7月10日喷施打顶剂可有效控制棉花株高，提高单株结铃数，优化棉花空间结构，进而提高产量和品质，以喷施土优塔效果较优。

关键词: 棉花, 打顶剂, 喷施时间, 农艺性状, 产量, 品质, 南疆