Effects Of Plant Density And DPC On Cottonseed Yield And Quality

Plant density and DPC are two important practices for field-grown cotton(Gossiypium hirsutum L),which have(great effects on cotton growth,canopy structure,biomass and lint yield.To providing theoretical basis for improving seed quality and achieving high yield,high quality and high efficiency of cottonseed,we studied the effects of plant density and DPC on cottonseed yield and quality.Field experiments were conducted in 2013 and 2014 at Dafeng Experimental Station in Dafeng(33�24'N and 120�34'E),Jiangsu Province,China.Three cotton cultivars,Siza 3 and Sikang 1 were used in the experiment.A split-plot design with three replications was used for this study.The main plot treatments were 135 g hn-2 of DPC and an untreated control,while plant densities of 13,500,25,500,37.500 and 49.500 plants hm-2 were assigned to the subplot treatments,respectively.We studied planting density and DPC on cotton growth,biomass,cottonseed yield and quality.The main results were as follows:1.Effects of plant density and DPC on cotton growth,biomass accumulation and distributionNo interactions were observed between plant density and DPC except plant height,fruiting branch,fruiting sites and bolls.Compared to the untreated control,plant height,abscission rate,mean fruit branch length and LAI were all reduced by applying DPC under different plant densities,while MC enhanced fruiting sites and bolls.Increasing plant density with or without MC significantly reduced fruit branch length.The highest of theoretical maximum of biomass accumulation,maximum of rate biomass accumulation in reproduction organs and reproduction organs-total biomass ratio were achieved at 37,500 plants hm-2.2.Effects of plant density and DPC on cottonseed yield and qualityThere were no significant interactions between plant density and DPC for cottonseed yield and quality.Cottonseed yield,oil yield and protein yield showed a parabolic increase as plant density increased,having the maximum values at 37,500 plants hm-2.Application of DPC significantly increased cottonseed yield,oil yield,protein yield,100-seed weight,100-embryo weight,oil content,soluble sugar content and sucrose content,indicating that applying DPC can promote cottonseed yield and quality.Besides,the responses of cottonseed yield,oil yield and protein yield to DPC tended to be stronger at low plant densities than at high plant densities.3.Effects of plant density and DPC on cottonseed vigorNo significant interactions were found between plant density and DPC for cottonseed vigor.Germination rate,germination percentage,germination index,vigor index and fresh weight of seeding were decreased as plant density increased.Compared to the control,germination rate,germination percentage,germination index,vigor index and fresh weight of seeding were enhanced by applying DPC.In addition,since 100-seed weight,100-embryo weight and oil content had a positive linear relationship with vigor index,they can determine the level of seed vigor.It was concluded that 37,500 plants hm-2 combined with applying DPC could be recommended for optimizing plant structure and achieving high cottonseed yield and quality in the Yangtze River cotton growing region of China.