Effects Of Nitrogen Rate On The Yield And Protein Quality In Strong Gluten Wheat And Its Physiological Basis

In order to explore the optimal nitrogen application rate and its physiological basis for high-yield,high-quality,high-efficiency,high-gluten wheat in the Easten Hebei Plain,two strong gluten wheat varieties,Shiyou 20 and Zhongmai 998,and set the nitrogen application rate 0（N₀）,180(N₁₈₀)and 240(N₂₄₀)kg·hm^-2,in 2017-2018.set the nitrogen application rate 0（N₀）,180(N₁₈₀),210(N₂₁₀)and 240(N₂₄₀)kg·hm^-2in 2018-2019,the amount of nitrogen applied to carbon metabolism（photosynthesis,dry matter accumulation and translocation,grain filling,yield）and nitrogen metabolism（nitrogen accumulation and translocation,nitrogen metabolism-related enzyme activity,protein content and component content,protein quality）.the result shows:Nitrogen application rate is in the range of 0-210 kg·hm^-2.Increasing the application of nitrogen fertilizer can significantly increase the chlorophyll content,thereby increasing the production of photosynthetic products,the accumulation and translocation of dry matter also increase,and the grain weight also increases accordingly.Compared with no nitrogen treatment,the yield of 180,210 and 240kg·hm^-22 nitrogen treatment was significantly improved.However,when the amount of nitrogen applied was 240 kg·hm^-2,compared with 210 kg·hm^-2,the chlorophyll content was reduced,which affected the production of photosynthetic products,and the dry matter translocation was also reduced.The weight gain of the grain was not significant However,its output has not increased significantly or even decreased,and its agronomic efficiency of nitrogen rate has also decreased significantly.Nitrogen application rate was in the range of 0-210 kg·hm^-2.With the increase of nitrogen application rate,the nitrogen accumulated before anthesis and transported after anthesis increased.The nitrogen transported amount at 14-21 d and 15-20 d after anthesis The largest,and based on the nitrogen transferred from the leaves as an important material basis,the activities of nitrogen metabolism-related enzymes,free amino acids and soluble protein content increased accordingly,the grain protein content also increased significantly,and the content of each protein component has increased to varying degrees,of which mainly storage proteins,which improves the processing quality of strong gluten wheat,the stability time,gluten content and sedimentation value have increased to varying degrees.However,when the amount of nitrogen applied was 240 kg·hm^-2,compared with 210 kg·hm^-2,the nitrogen transport amount decreased,the activities of nitrogen metabolism-related enzymes,free amino acids,and soluble protein content decreased,and the grain protein content also Decrease,the stability time,gluten content and settlement value and other indicators have been reduced to varying degrees.In summary,too high and too low nitrogen application rates are not conducive to improving yield,quality and agronomic efficiency of nitrogen rate.Under the conditions of this experiment,when the nitrogen application rate is 210 kg·hm^-2,the yield is higher,the protein content and processing quality are better,and the agronomic efficiency of nitrogen rate is effectively improved.Therefore,the optimal nitrogen application rate for strong gluten wheat cultivation in the Easten Hebei Plain is 210 kg·hm^-2.