The Effects Of Chemical Topping On Agronomic Trait And Yield Of Cotton By Drip Irrigation

?Objective?Through the study of plant growth regulators compounded as chemical topping agents which could inhibit effectively bud growth,and result in a more compact plant compared with manual topping,this achieves the goal of manual topping.The objectives of this experiment were to study the effects of two chemical topping agents in the production of cotton by drip irrigation in the fifth division,Flumetralin and Mepiquat chloride,on the characteristic of plant morphological,yield of cotton;to explore the maximum benefit of chemical topping agents of cotton by drip irrigation under reasonable water and fertilizer management condition;to determine how topping way affect defoliation ripening effect.The results of this study provide increased understanding that could be used for more effective use of chemical topping agents.?Methods?The study included Xinluzao 42,64,Xinluzhong 77 three cotton cultivars.Conventional manual topping was the control treatment.To measure cotton agronomic traits and yield changes to analyze the effect on cotton height and yield of Chemical topping and the effects on cotton leaves reddening changes in the physiological characteristics of premature aging under different topping ways;To measure the rate of shed leaves,the rate of hanging leaves,the rate of boll open,exploring the influence of cotton by drip irrigation plant type and application time on cotton leaves shedding.?Results?Plant height,number of main stem section and main stem leaf number were significantly greater and after spraying growth was larger in the chemically-topped treatments than in the manually-topped treatment;The length of the branch of the upper layer and plant wide were significantly lesser in the chemically-topped treatments than in the manually-topped treatment,and lateral growth was inhibited significantly at after spraying.Cotton chemical topping could reduce cost of production,but cotton fiber quality of the chemically-topped treatments didn't affect.According to a survey conducted from 2016 to 2017,the cost of chemical capping of drip irrigation cotton is 24.6 % lower than that of manual capping.The POD and SOD activities of different cotton varieties were shown to be higher in artificial pruning than in chemical pruning.The MDA content of different cotton varieties showed that the chemical pruning treatment was higher than the artificial pruning treatment.The total fruit branch numbers and boll number per were greater in the chemicallytopped treatments than in the manually-topped treatment.Cotton yield in the Flumetralin treatment was greater than that in the manually-topped treatment.The rate of shed leaves and the rate of boll open were greater in the chemically-topped treatments than in the manually-topped treatment;the rate of hanging leaves was lesser in the chemically-topped treatments than in the manually-topped treatment.?Conclusions?Cotton chemical topping agents can inhibit effectively apical dominance and control lateral growth of branch and shape compact plant type and influence the formation of cotton canopy structure.The number of bolls per plant and yield of drip irrigation cotton increased under the treatment of chemical capping.Chemical capping and finishing agents promote aging of cotton plants.The compact plant type and reasonable canopy light distribution of chemical topping cotton improved cotton defoliation ripening effect.