Relationship Between Grain Nitrogen Content and Yield Formation,Uptake and Partitioning of NPK of High-Yielding Wheat Cultivars in Drylands
[Objective]The aim of this study was to understand the variations of grain nitrogen(N)content and its relationships with yield formation as well as uptake,transfer and partitioning of nitrogen,phosphorus,and potassium(NPK)within high-yielding wheat cultivars,which was of great significance for screening and breeding superior wheat cultivars with high yield and grain N content,and for nutrient management in green production of wheat with high yield and high quality in drylands.[Method]Field experiments were carried out,and 14 high-yielding wheat cultivars of similar yields and different grain N content were cultivated on the typical dryland area of the Loess Plateau from 2017 to 2022.Differences in grain N contents of high-yielding wheat cultivars and its relation to yields,yield components as well as N,P and K content in different organs were analyzed.Meanwhile,biomass accumulation and yield formation as well as uptake,transfer and partitioning of NPK in response to fertilization were investigated.[Result]Significant positive correlation was found between the grain N content and 1000-grain weight of wheat cultivars,and for each 1.0 g increase of the 1000-grain weight,the grain N content increased by 0.3 g·kg-1.The grain N content showed significant differences in the tested wheat cultivars,with the mean of high-N group being 24.9 g·kg-1,and 16％higher than that of the low-N group(21.5 g·kg-1),respectively,while the average yields were not significantly different from each other of the two groups.The yield,biomass and spike number of high-N group exhibited higher response to N and P fertilizer application.The grain P content and straw K content of the high-N group were higher than the low-N group under different fertilization conditions,and the increases of N,P and K uptake in grain and shoot were larger than that of low-N group after N and P application.The abilities of N transfer from glumes to grains in the high-N group was greater than that in the low-N group,but the capacities of K transfer from straws to grains and glumes was lower than that in low-N cultivars.The abilities of K transfer from straws to other organs decreased significantly after N application.Application of N,P and K was conducive to increase the partitioning of K from shoots to straws of the high-N group.[Conclusion]The high-yielding wheat cultivars exhibited significant differences in the grain N content.The 1000-grain weight and grain P content of high-N cultivars were higher,its straw K content was also higher,but its capacities of K transfer from straws to grains and glumes was lower.The N,P and K uptake of the high-N group in grains and shoots increased extremely after N and P application.Therefore,to screen and breed superior wheat cultivars with high grain N content on the basis of high yield,the attention should be paid to select the cultivars with high grain 1000-grain weight as well as the strong transferring and partitioning abilities of P to grains and K to straws.The efforts should be also made to cooperate the supply of P,K and N in wheat production,with the purpose to increase the grain N content.
drylandhigh-yielding wheat cultivarsgrain N contentnutrient uptakenutrient transfernutrient partitioningwheat yield
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