Effects Of Sowing Date,planting Density And Nitrogen Management On Grain Yield,nitrogen Uptake And Utilization And Quality Of Strong Gluten Wheat

In order to solve the contradiction of yield,quality and efficiency in strong gluten wheat production in China,the strong gluten wheat Gaoyou 5766 was used as the experimental material.Two sowing dates（October 8 and October 22）,two N fertilization levels(180 and 240kg ha^-1),two N topdressing ratios（5:5 and 3:7）and three planting densities(180,270 and 360plants m^-2)were set in this experiment.To study the effects of sowing date,planting density and nitrogen management and their interactions on yield,nitrogen uptake and utilization and quality of wheat.The results are as follows:1 The effects of sowing date,planting density and nitrogen management and their interactions on wheat yield and yield componentsThe sowing date was postponed from October 8 to October 22,the increase of kernels per spike and 1000-seed weight compensated for the decrease of spike numbers per unit area,and the grain yield was stabilized.When N fertilization level was increased from 180 kg ha^-1 to 240kg ha^-1,the increase of spike numbers per unit area and kernels per spike was higher than the decrease of 1000-seed weight,so the grain yield increased.When N topdressing ratio was adjusted from 5:5 to 3:7,the spike numbers per unit area and kernels per spike increased,the1000-seed weight had no significant change,so the grain yield increased.When the planting density increased from 180 plants m^-2 to 270 plants m^-2,the increase of spike numbers per unit area was higher than kernels per spike,and the grain yield increased.When the planting density increased to 360 plants m^-2,the grain yield decreased.Under the experimental conditions,sowing dates and N fertilization levels had significant interaction on grain yield and yield components of strong gluten wheat.When N fertilization level was 180 kg ha^-1,the number of spikes per unit area decreased significantly due to delayed sowing date,which the grain yield decreased.When N fertilization level was 240 kg ha^-1,the increase of kernels per spike and 1000-seed weight could compensate for the decrease of spike numbers per unit area after delayed sowing date,so as to maintain the stable grain yield.2 The effects of sowing date,planting density and nitrogen management and their interactions on nitrogen use efficiency of wheatThe sowing date was postponed from October 8 to October 22,the increase of nitrogen utilization efficiency（UTE）compensated for the decrease of nitrogen uptake efficiency（UPE）,so the nitrogen use efficiency（NUE）was stabilized.When N fertilization level was increased from 180 kg ha^-1 to 240 kg ha^-1,UPE and UTE decreased,resulting in NUE decreased.When the ratio of N topdressing and planting density were increased,the increase of the UPE was higher than the decrease of UTE,which led to the increase of NUE.When planting density was further increased,NUE decreased.Under the conditions of this experiment,there was a significant interaction between sowing dates and N fertilization level on nitrogen use efficiency of strong gluten wheat.When N fertilization level was 180 kg ha^-1,the decrease of the UPE was higher than the increase of UTE,and NUE decreased.When N fertilization level was 240 kg ha^-1,the increase of UPE could compensate for the decrease of UTE after delayed sowing date,which kept the NUE stable.3 The effects of sowing date,planting density,nitrogen management and their interactions on grain qualityWith the delay of sowing date,and the water absorption of wheat remained stable,while the dough development time and dough stability time decreased.When the N fertilization level was increased,the N topdressing ratio was increased and the planting density was increased to270 plants m^-2,the water absorption was increased or remained unchanged,and the dough development time and dough stability time were increased.Further increases in planting density will reduce the dough development time and dough stability time.Under the experimental conditions,the effects of sowing dates and N fertilization levels on dough development time and dough stability time of strong gluten wheat had significant interactions.When N fertilization level was 180 kg ha^-1,the dough development time and dough stability time were decreased after delaying sowing date.When N fertilization level was 240 kg ha^-1,the dough development time and dough stability time of wheat could be improved after delaying sowing date.With the delay of sowing date,the protein content,glutenin content,glutenin/gliadin,HMW-GS and LMW-GS of strong gluten wheat decreased except that the gliadin content increased and the polymerization index remained unchanged.The protein content,gluten content,gliadin content,glutenin content,glutenin/gliadin,polymerization index,HMW-GS and LMW-GS of strong gluten wheat increased with the increase of N fertilization level,N topdressing ratio and planting density to 270 plants m^-2,while the planting density decreased with the increase of planting density.Under the conditions of this experiment,the effects of sowing dates and N fertilization levels on protein components of strong gluten wheat had significant interactions.When N fertilization level was 180 kg ha^-1,protein content,gluten content,gliadin content,glutenin/gliadin,polymerization index,HMW-GS and LMW-GS of strong gluten wheat were decreased after delayed sowing date.The protein content,glutenin content,gliadin content,polymerization index,HMW-GS and LMW-GS of strong gluten wheat were significantly increased after delayed sowing date except that the glutenin/gliadin decreased at 240 kg ha^-1 N fertilization.4 The collaborative way of yield,nitrogen use efficiency and quality of strong gluten wheatUnder the conditions of this experiment,the yield,quality and nitrogen use efficiency of strong gluten wheat could be coordinated with the planting density of 270 plants m^-2 and the N fertilization level of 240 kg ha^-1,N topdressing ratio of 3:7,which were sown on October 22.