Abstract: To explore the regulating effect and potential of yield increase of prohexadione calcium on cotton,and to provide scientific basis for high-yield cultivation in Xinjiang cotton area. This experiment was conducted in Dafeng Town,Hutubi County,Xinjiang,and Sidaohezi Town,Shawan County,Xinjiang in 2019. A randomized block test design was used. The test used DPC as a control(CK)and four prohexadione calcium doses were set:T1(750 g/ha),T2(1 350 g/ha),T3(1 950 g/ha)and T4(2 550 g/ha), at the bud stage,early flowering stage,topping spray in divided doses before and after topping. Dry matter accumulation,agronomic characters,yield and quality of cotton were investigated. The daily growth of main stem increased first and then decreased with time after spraying prohexadione calcium,and reached the peak after two applications(the early flowering period).The regulation effect of prohexadione calcium on plant height had a certain dose effect. With the increase of the dose,it increased first and then decreased. The inhibitory effect was most significant at the T3 level. Boll opening period of cotton plant height at the two test sites increased by 3.35%,7.15% compared with the control. At the same time,prohexadione calcium increased the biomass accumulation of cotton above ground parts,and the biomass of T3 reproductive organs was increased by 35.07%,34.35% at the two test points respectively;the leaf branches treated with prohexadione calcium were 3.89-14.34 cm longer than the control,and the first fruit branch were higher than the control length 4.83-10.16 cm,the fourth fruit branch were higher than the control length 3.34-12.34 cm; compared with the control, the number of bolls per plant of fruit branches of cotton treated with prohexadione calcium increased by 4.90%-23.04%,and the yield of seed cotton increased by 226.14-907.87 kg/ha,both of which were the same T3 has the highest yield,with lint cotton yields of 2 885.66,2 879.53 kg/ha,while prohexadione calcium has the effect of optimizing fiber quality. Spraying 1 950 g/ha of 5% prohexadione calcium during the whole growth period could significantly control cotton plant height,shape high-yield plant types,effectively coordinate the relationship between vegetative growth and reproductive growth,significantly increase cotton yield and improve fiber quality.

Key words: Cotton, Prohexadione calcium, Plant type regulation, Agronomic traits, Cotton yield, Fiber quality

CLC Number: 

• S562.01