摘要：[Objectives] It is of great importance to clarify the variation of grain nitrogen (N) content and the related main agronomical and nutritional constraining factors for the variation.The research will provide theoretical supporting for improving wheat grain yield and nutritional quality through breeding and regulating fertilizer application.[Methods] Field experiments were conducted in the typical dryland area of the Loess Plateau from 2013 to 2016,123 wheat cultivars were collected from the main wheat production areas of China.No fertilization control and treatment of applying N 150 kg/hm2、P2O5 100 kg/hm2 were setup.The yields were investigated and the grain N,P and K contents were determined after harvest.Those with yields higher than average were defined as high-yielding cultivars,of them,the top ten and last ten cultivars in grain N content were chosen as high-N and low-N group respectively.The relationship of grain N contents with dry matter accumulation,yield components and the uptake and utilization of N,P and K were calculated.[Results] A significant negative correlation was found between the grain yield and grain N content in all the tested wheat cultivars,and for every 1000 kg/hm2 increase of grain yield,the grain N content was decreased by 1.1 g/kg.For the cultivars at the same high-yielding level,the grain N contents also showed significant differences.The average grain N content of the high-N group was 24.2 g/kg,24.7％ higher than that of the low-N group (19.4 g/kg).Significant differences between the high-N and low-N groups were also observed in the grain yield,biomass and yield components,and the high-N group exhibited higher responses to fertilization,with grain yield increased by 70.0％,biomass by 60.2％,harvest index by 9.8％,spike number by 51.6％ and grain number per spike by 14.3％,respectively.The vegetative part N content of the high-N group showed a 150.0％ increase after fertilization,while P and K contents decreased significantly.Under the condition of sufficient soil nutrient,vegetative part N contents of the high-N group was always higher than those of the low-N group,the P and K contents showed no significant difference between the two groups,and the increase of K content was greater than that of P content after fertilization.The aboveground part N and P uptake of the high-N group was higher than that of the low-N group,especially in grain,but grain K uptake of the high-N group was significantly lower than that of the low-N group whether fertilizer was applied or not.When fertilizer was applied,the aboveground part N,P and K uptakes of the high-N group were increased much more than those of the low-N group,and the corresponding increase of vegetative part was more than that of grain.No significant differences were found in the N and P harvest indexes between the two cultivar groups,while the K harvest index averaged over three years for the high-N group was significantly lower than that for the low-N group.[Conclusions] Under conditions of sufficient nutrient supply in drylands,the differences of grain yield,spike number,grain number per spike and thousand grain weight were not significant between the high-N and low-N wheat cultivars at high-yielding levels,while the high-N cultivars were more sensitive to fertilization.The high-yielding cultivars showed significant differences in the grain N content,and the high-N cultivars were observed with high grain P but low grain K contents.After fertilization,the N contents of high-N cultivars were increased,but the P and K contents were decreased.The high-N cultivars possessed higher N,P and K uptakes,but not superior in the shoot N,P and K translocation to grains than the low-N cultivars.Therefore,more efforts should be made to enhance the N,P and K harvest indexes and their translocation to grains in future wheat breeding,and attention should be paid to optimize fertilizer input and promote the crop N,P and K uptake and utilization,to realize simultaneously the increase of grain N,P and K contents and yields.%[目的]调查高产小麦品种籽粒氮含量差异,探讨引起籽粒氮含量差异的主要农学和营养学因素,对于品种选育和优化养分管理,提高旱地小麦产量与营养品质有重要意义.[方法]于2013-2016年,以我国不同麦区的123个小麦品种为供试材料,在陕西渭北旱塬连续三年开展田间试验.设置施肥(N 150 kg/hm2、P2O5 100 kg/hm2)和不施肥对照两个处理,收获后测产.在产量高于平均值的品种中,籽粒含氮量列前10名的定义为高氮品种,后10名的为低氮品种.分析了高产小麦品种植株和籽粒氮、磷、钾含量,干物质累积,产量构成及氮磷钾吸收利用的关系.[结果]小麦籽粒含氮量与产量呈极显著负相关,高产品种平均产量为6.9 t/hm2,籽粒产量每增加1000 kg/hm2,含氮量平均降低1.1 g/kg.高产品种间籽粒氮含量差异显著,高氮品种的籽粒含氮量平均分别为24.2 g/kg,低氮品种平均为19.4 g/kg,相差24.7％.两组品种的产量、生物量和产量构成因素差异均不显著,高氮品种的产量、生物量、收获指数、穗数和穗粒数对氮肥响应更敏感,施肥后分别显著增加70.0％、60.2％、9.8％、51.6％和14.3％,高氮品种营养器官含氮量较高,施肥后可显著增加150.0％;高、低氮品种籽粒的磷钾含量无显著差异,施肥后钾含量增加幅度均大于磷含量增加.高氮品种施肥后地上部氮、磷吸收量高于低氮品种,籽粒积累量增加幅度高于营养器官;籽粒钾吸收量无论施肥与否均显著低于低氮品种.施肥后,高氮品种地上部氮磷钾吸收量增幅高于低氮品种,营养器官的增幅高于籽粒.两类品种的氮磷收获指数无显著差异,但高氮品种的钾收获指数三年平均显著低于低氮品种.[结论]旱地土壤养分供应充足条件下,高产小麦高、低籽粒氮品种的产量、穗数、穗粒数和千粒重均无显著差异,但高籽粒氮品种对施肥响应更敏感.高产小麦品种间籽粒氮含量存在显著差异,高氮品种的籽粒含磷量高,含钾量低.施肥后,高氮品种的籽粒氮含量提高,磷、钾含量降低.高氮品种具有较高的地上部氮磷钾吸收量,但其向籽粒的转移能力并无优势.因此,在高产优质品种选育中,应进一步提升品种的氮磷钾收获指数,促进养分向籽粒分配,同时生产中需优化肥料投入,促进籽粒氮磷钾吸收与利用,实现产量和籽粒氮磷钾含量同步提高.