目的 在不同灌水量条件下研究增效缩节胺(1,1-dimethyl-piperidinium chloride,缓释型水乳剂,简称DPC⁺)对棉花化学封顶的效应,为完善新疆棉花化学封顶技术提供依据。方法 以早熟陆地棉品种新陆早53号为材料,设置不同的灌水量(3000,4800,6600 m³·hm^-2)和DPC⁺剂量(450,750,1050 mL·hm^-2),测定棉花农艺性状、生理特性及产量和品质等指标。结果 棉花株高和单株果枝数随DPC⁺剂量的增加而下降,低(450 mL·hm^-2)、中(750 mL·hm^-2)、高剂量(1050 mL·hm^-2) DPC⁺处理的株高和单株果枝分别比人工打顶增加9.4 cm和4.8个,6.2 cm和3.9个,2.2 cm和2.6个。中等灌水量(4800 m³·hm^-2)下棉花产量最高,比低灌水量(3000 m³·hm^-2)处理增产20%左右,比高灌水量(6600 m³·hm^-2)处理增产5%左右。低、中、高灌水量下,分别以低、中、高剂量DPC⁺的产量最高,一般较人工打顶提高5%~10%。低灌水量下低剂量DPC⁺处理主要依靠较大的群体生物量获得相对较高的产量,高灌水量下高剂量DPC⁺处理主要依靠较高的产量器官干物质分配率获得相对较高的产量,而中等灌水量下中等剂量DPC⁺处理的产量在所有处理中最高,得益于比较适宜的冠层生产能力和合理的干物质分配能力。结论 灌水量需要与DPC⁺剂量互相配合,在增加群体物质生产能力的同时保障营养生长和生殖生长协调,这是提高棉花DPC⁺化学封顶技术成功率的关键途径之一。

[Objective] 1,1-dimethyl-piperidinium chloride (DPC) has been widely used for cotton (Gossypium hirsutum) production. Fortified DPC (DPC⁺) is a slowly released emulsion (i.e., oil and DPC prepared in water) that is more active than normal soluble DPC powder. The role of DPC⁺ in cotton treatments was determined using different amount of water provided in a drip irrigation system. The results may be useful for improving chemical toppings involving DPC⁺. [Method] Cotton variety Xinluzao 53 plants were grown using a drip irrigation system (i.e., 3000, 4800, or 6600 m³·hm^-2), and DPC⁺ (i.e., 450, 750, or 1050 mL·hm^-2) was applied in early July with manual toppings. Agronomic traits, some physiological traits, yield, and fiber quality were analyzed. [Results] Plant height and the number of fruit branches per plant decreased with increasing DPC⁺ doses. The plants treated with low (450 mL·hm^-2), moderate (750 mL·hm^-2), and high (1050 mL·hm^-2) DPC⁺ doses were 9.4, 6.2, and 2.2 cm taller than the control plants, respectively. Additionally, the number of fruit branches per plant increased by 4.8, 3.9 and 2.6, respectively. The moderate irrigation treatment (i.e., 4800 m³·hm^-2) resulted in the highest yields, which were about 20% and 5% greater than that of low (3000 m³·hm^-2) and high irrigation (6600 m³·hm^-2) treatments, respectively. Regarding yield, there was a significant interaction between the amount of water and DPC⁺ dose. The low, moderate, and high DPC⁺ doses produced the highest yields with low, moderate, and high irrigation treatments, respectively. The low DPC⁺ dose produced greater yields with the lowest irrigation treatment mainly because of the relatively high above-ground plant biomass. The high yield obtained with a high DPC⁺ dose and high irrigation treatment was associated with the large proportion of dry mass in plant reproductive parts. The moderate DPC⁺ dose and irrigation treatment produced the highest yield among all treatments because of ideal dry mass accumulation and plant biomass distribution. [Conclusion] Manual toppings of DPC⁺ may be replaced by the application of an ideal combination of DPC⁺ and water in a drip irrigation system.