Study On The Differences In Nitrogen Efficiency Among Different Varieties Of Wheat In The Mound Of Northern Hubei

The mound of northern hubei are main areas of winter wheat production in hubei province.Unreasonable application of nutrients,especially nitrogen are key factor that restricted the development of agricultural production in these areas. It is an important way in rational utilizing resources, decreasing environmental pollution and reducing inputs that exploiting plant descendible characteristics and potential of nutrients use, cultivating or utilizing variety with high nutrition use efficiency, among these methods and approaches.On the basis of study over having past several years,through the field experiment and the pot experiment, Five local dominating winter wheat varieties(EM14,EM18, EM23,ZM9023,LM1)were selected under high nitrogen application(195kg/hm2)and no nitrogen application(0kg/hm2), The difference of the internal mechanism were researched from the evaluating indicator of nitrogen use efficiency of wheats, the difference of the varieties and the physiological metabolism, the accumulation & distribution of dry matter and nitrogen, root characteristics by using the techniques about analysis of growth dynamics and physiological testing et al. The formation mechanism of high nitrogen efficiency furthermore were analyzed in order to provide the theoretical basis for using genetic characteristics to improve nitrogen use efficiency (NUE)of winter wheats and cultivate the varieties which could use nitrogen efficiently.The results are obtained as followed:1. nitrogen fertilizer application could significantly increase the biomass,grain yield and harvest index of different winter wheats; the same time, it could significantly promote the constituent elements of grain yield of the different wheat varieties to increase.Compared with the no nitrogen treatment,the biomass yield of the different wheat varieties with nitrogen application raised by 72.09%～207.39%;the grain yield raised by 176.69%～409.89%;the effective tillers raised by 37.6%～75.1%;the grain number Per spike raised by 46.9%～157.3%;1000-grain weight increased by 1.0%～9.9%. The yield, the grain number Per spike and 1000-grain weight of LM1 and EM14 with nitrogen treatment were significantly higher than other varieties. Compared with no nitrogen treatment,the range increase of the yield, the grain number per spike and 1000-grain weight of LM1 were the largest.2. Nitrogen efficiency of the different wheat varieties were significantly different. In aspect of the responsiveness, each lkg nitrogen fertilizer rising lead to the grain yeild increase of 17.8kg～28.7kg of the different wheat varieties,in which the responsiveness of LM1 was highest. In aspect of the sentivity,each 1kg nitrogen fertilizer rising lead to the amount of nitrogen uptake increase of 0.4kg～0.8kg of the different wheat varieties,in which the sentivity of EM23 was the highest, EM 14 was the second,LMl was the lowest. Compared with no nitrogen application,the index of nitrogen efficiency of the different winter wheat varieties with nitrogen application increased significantly (NUE excluded),in which the NUE and the nitrogen harvest index of EM14 and ZM9023 were higher. The nitrogen uptake efficiency and the nitrogen flow efficiency of EM14 and LM1 were higher than the other varieties and their grain yield were also higher.3. After anthesis, the physiological indicators and urease activity of the soil of the winter wheat varieries with high nitrogen efficiency were higher.In the condition of nitrogen and no nitrogen application,analyzing the chlorophyll content, the nitrate reductase activity and the urease activity of soil of the different winter wheat of varieties at the five growing stage (wintering stage, reviving stage, jointing stage, anthesis stage, grain filling stage). Compared with no nitrogen treatment, the physiological indicators above all with nitrogen treatment were significantly higher. The chlorophyll content and nitrate reductase activity of leaf of EM14 LM1 were relatively higher and the urease activity of the soil of EM14 and LM1 were higher too.4. The root activity and the morphological index of the different winter wheat of varieties was significantly different. In the condition of nitrogen stress,the seedling appearred. The value of the root length of LM1 was significantly different with the other varieties and it was maximum. Nitrogen application promoted Varieties the root length, root surface area, root dry weight of the winter wheat of varieties to raise significantly. However, compared with no nitrogen treatment ,the root length, root surface area of LM1 with nitrogen treatment decreased. In the condition of nitrogen application, the root activity of EM14 and LM1 were significantly higher than the other varieties, but the difference between them was not significant. In the condition of nitrogen application, the root activity of LM1 was significantly higher than the other varieties.5. At different growth stages, the dry matter accumulation and transfer of the different winter wheat of varieties were significantly different. the dry matter remobilization quantity of the different winter wheat of varieties as follows:stem> spike> leaves. In the condition of no nitrogen application, from anthesis stage to filling stage, the dry matter remobilization quantity in stem of the winter wheats raised by 11.76%～43.21%; the dry matter remobilization quantity in leaves raised by 4.84%～41.03%; the dry matter remobilization quantity in spike increased by 26.65% 166.47%. The dry matter accumulation in the stem, leaf and spike of witer wheats with nitrogen treatment increased by 10.05%～23.45%,5.05%～8.50% and 5.90%～13.78%. After anthesis, the dry matter accumulation in spike of LM1 with nitrogen application was the highest. In the condition of no nitrogen application, the dry matter remobilization quantity in spike and stem of EM14 were higher than the other varieties; the dry matter remobilization quantity in leaf of ZM9023 was higher than the other varieties;The dry matter remobilization rate and the contribution to grain of dry matter remobilization in leaf of LM1 was the highest;the dry matter remobilization rate and the contribution to grain of dry matter remobilization in spike and stem of EM14 was higher than the other varieties. In the condition of nitrogen application, nitrogen fertilizer promoted the dry matter remobilization quantity of different nutrition organs of the different wheat varieties to raise substantially, The dry matter remobilization quantity, remobilization rate and the contribution to grain in stem of LM1 were higher than the other varieties.6. There was significant difference in the characteristics about nitrogen uptake, transport and redistribution of winter wheat of varieties. After anthesis, Nitrogen accumulation in stem, leave and spike of EM14 with no nitrogen treatment were the highest, the remobilization rate of nitrogen in different organs transferred to the grain was higher than the other varieties and nitrogen accumulation in grain was the highest. There was a bigger change range about nitrogen accumulation and remobilization rate in different organs of the different wheat of varieties with nitrogen treatment. Nitrogen accumulation in leaves of EM23 was the highest;nitrogen accumulation in stem of EM14 was the highest; nitrogen accumulation in spike of EM18 was the highest and nitrogen accumulation in grain of EM14 was still the largest.At maturity stage, nitrogen accumulation and distribution rate in different organs had a significant reduction, nitrogen transfer from the different organs to grain and the nitrogen accumulation in grainof EM14 was the biggest. Nitrogen fertilizer significantly promoted nitrogen remobilization quantity in different organs of the different wheat of varieties to increase, nitrogen remobilization quantity of EM14 and LM1 in stem were higher than the other varieties. nitrogen remobilization quantity in leaf of EM18 and EM23 were higher; nitrogen remobilization quantity in spike of EM14 and EM18 were higher. The contribution to grain of nitrogen remobilization in stem of EM14 and LM1 were higher than the other varieties.