关键词: 机采棉; 氟节胺; 缩节胺; 化学调控技术

Abstract: 【Objective】 To analyze and compare the effects of different doses of flumetralin and DPC on the plant type structure of machine-harvesting cotton, and provide a theoretical basis for the chemical regulation in the middle and late stages of cotton.【Method】 In this paper, two plant growth regulators, flumetralin and DPC used in cotton production were selected and applied at the bud stage, the initial flowering stage and the topping stage of cotton with the artificial detopping cotton as a control group.【Result】 The results showed that after spraying flumetralin and DPC for the first time, the growth amount of cotton plant height was between 15.00 cm and 27.00 cm. Except the treatment groups such as flumetralin 300 g/hm² + DPC 30 g/hm²、 flumetralin 300 g/hm² + DPC 50 g/hm² and flumetralin 600 g/hm² + DPC 30 g/hm², the growth amount of cotton plant height of other treatments were shortened by about 4.89-12.43 cm (P<0.05). After the second application of these two drugs, the growth amount of cotton plant height was between 2.00 cm and 7.59 cm, The plant height growth of cotton treated with flumetralin 300 g/hm² + DPC 30 g/hm², flumetralin 300 g/hm² + DPC 50 g/hm², and flumetralin 600 g/hm²+ DPC 50 g/hm², increased by 3.08-4.69 cm (P<0.05). After the third application of these two drugs, the cotton plant height of each treatment and artificial topping did not increase substantially.When flumetralin was 600, 900, 1,500 g/hm² + DPC 70 g/hm², the number of effective branches of cotton increased by 7.75%-10.64%. When machine-harvesting cotton was sprayed with flumetralin 600, 900, 1 500 g/hm² + DPC 70g/hm², the number of cotton effective fruit branches increased by 7.75%-10.64%, However the average length of first fruit branch, top 2nd fruit branch, top 3rd fruit branch decreased by 8.23-9.68 cm (P<0.05). Spraying flumetralin and DPC, the upper boll of the cotton plant increased by 19.72%-71.85%, while the central boll increased by 5.71%-32.65% only when the concentrations of flumetralin were 600, 900, 1,500 g/hm². When machine-harvesting cotton was sprayed with flumetralin and DPC, the upper cotton bolls increased by 19.72%-71.85%, while the central cotton bolls increased by 5.71%-32.65% only when the concentrations of flumetralin were 600, 900, 1,500 g/hm².【Conclusion】 After application flumetralin and DPC, the plant height can be effectively controlled, and when the concentrations of the two agents are higher, the population structure can be better optimized.

Key words: machine-harvesting cotton; flumetralin; DPC; chemical regulation techniques