| Reducing investment and improving efficiency has become the future development direction of China’s agriculture. For the problem of a large number of inputs of nitrogen utilization and low efficiency in wheat production process, wheat varieties with different nitrogen efficiency were divided and the effects of reducing nitrogen to wheat varieties with different types of nitrogen efficiency were researched, which has important implications for saving costs and increasing efficiency, nitrogen application optimization in wheat production process. The main findings are as follows:The relationship between yield and nitrogen physiological efficiency of 29 wheat varieties showed that yield and nitrogen physiological efficiency were a significant positive correlation(F = 0.544 **). Using cluster analysis method, the 29 wheat varieties were classified into four types, the first type was high nitrogen high efficiency(HH) type, such species included: Zhengmai 366, Zhoumai 27, Xinmai 19, Hengguan35, the yield range was 10174.0-11024.2 kg ? hm-2; the second type was high nitrogen low efficiency(HL) type, such species included: Yunong 416, Zhoumai 26, Xinong 509, Yunong 202, Zhoumai 28, Aizao 8, Kaimai 20, Luomai 24, the yield range was 7576.9-8212.0 kg ? hm-2; the third type was low nitrogen high efficiency(LH) type, such species included: Zhengmai 366, Luomai 18, Xuke 316, Zhongyuan 6, Yumai 49-198, Zhoumai 27, the yield range was 8798.2-8999.7 kg ? hm-2; the fourth type was a low nitrogen low efficient(LL) type, such species included: Kaimai 20, Luomai 24, Aizao 8, Yanzhan 4110, Zhongyu 9398, Zhoumai 26, Zhengmai 3596, Xinong 509, Yunong 202, Aikang 58, the yield range was 7164.4-7534.3 kg ? hm-2. After binding nitrogen physiological efficiency, Zheng Mai 366 and Zhou Mai 27(HH), Kai Mai 20 and Zhou Mai 28(HL), Luo Mai 18 and Yu Mai 49-198(LH), Xi Nong 509 and AK 58(LL) were selected to study differences of characteristics of nitrogen metabolism.Analysis of yield of wheat varieties with different types of efficieicy showd that, under normal application of NN225 conditions, yield of four types wheat varieties showed HH> LH> HL> LL. Under N120 conditions, the differences of the four types of varieties were consistent with that under N225 conditions. The yield of HH, HL, LH, LL decreased by 9.40%, 2.27%, 4.85%, 10.59%, indicating that in the case of reducing the amount of nitrogen, decreasing amplitude of HH and LL was greater.The results of aboveground nitrogen accumulation and distribution of wheat varieties with different types of nitrogen efficiency showed that, under N225 conditions, The average aboveground nitrogen accumulation of HL was higher than that of LL in flowering stage and maturity, nitrogen accumulation and distribution rate of spike in flowering stage and grain in maturity showed that HH were significantly higher than HL, LH were significantly higher than LL. Under N120 conditions. The difference between the four types of species was consistent with the N225, aboveground nitrogen accumulation in flowering stage of HH, HL, LH, LL reduced 13.89%, 15.20%, 12.16%, 9.86%, and it was HH <HL, LH <LL; nitrogen accumulation of spike of the four types reduced 30.76%, 16.84%, 28.35%, 16.98%, and it was HH> HL, LH> LL; aboveground nitrogen accumulation in maturity reduced 15.77%, 12.84%, 14.80%, 17.97%, and it was HH> HL, LH <LL; nitrogen accumulation of grain decreased 16.76%, 14.38%, 16.63%, 20.68%.The results of nitrogen translocation amount and transfer efficiency of wheat varieties with different types of nitrogen efficiency showed that, under N225 process, the amount of nitrogen translocation before flowering of HL was significantly higher than that of HH, and LH was significantly higher than LL; Contribution of translocated Nitrogen to grain Nitrogen of HL was significantly higher than that of HH, and LL was significantly higher than LH; Nitrogen absorption amount after anthesis and Contribution of postantheis Nitrogen absorption amount to grain Nitrogen of HH was significantly higher than HL, and LH was significantly higher than LL. Under N120 Handling, except for the amount of nitrogen translocation before flowering was HL> HH, LL> LH, the other indexes were consistent with proper nitrogen conditions. The amount of nitrogen translocation before flowering of HH, HL, LH, LL decreased by 14.32%, 18.46%, 13.37%, 7.74%; nitrogen absorption amount after anthesis of HH, LH, LL decreased by 20.68% %, 22.11%, 49.84%, and that of HL rosed slightly by 0.98%.The morphological indicators of wheat varieties with different types of nitrogen efficiency showed that, under N225 process, dry matter accumulation of HH was general less than that of HL during winter to 21 days after flowring, and it was Zhoumai 28 > Zhoumai 27> Zhengmai 366> Kaimai 20 in maturity; and LH and LL were significantly different in different periods, it was LH > LL. Leaf area index of HH and LH were higher as a whole. Under N120 process, the dry matter accumulation and leaf area index of the foure types of varieties were more of consistent with normal application of N, decreasing amplitude of dry matter accumulation and leaf area index of HH and LL was larger.The nitrogen metabolism physiological indicators of wheat varieties with different types of nitrogen efficiency showed that, under N225 process, GS activity, free amino acids, soluble proteins, NO3- and total nitrogen content in leaf, peduncle, glume and grain were consistent overall, it was HH was significantly higher than HL, LH was significantly higher than LL. Under N120 treatment, related physiological indices of different organs were consistent with N225, the declines of GS activity, free amino acids and soluble protein in leaf, peduncle, grain and glume were HH> HL, and declines of NO3- in leaf and peduncle of HL were larger; related physiological indices of LL were overall significantly higher than that of LH. |
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