Difference In Grain Nitrogen And Phosphorus Contents Of High-yielding Wheat Cultivars And Its Relation To Yield Formation And Nutrients Uptake And Utilization In Drylands

Wheat is one of the three major crops.The grain yield was 280 million tons of dryland in2014,accounting for 47%of the total grain yield in China.The wheat planting area in the Loess Plateau accounts for 44%of the crop planting area,and the yield accounts for 35%of the grain yield in the region.Guaranteeing dryland wheat yield is important for regional and national food security.The continuous input of fertilizer in the process of improving wheat yield and improving wheat quality in northwestern dryland has also brought enormous pressure on the environment,and difficult to achieve sustainable enhancement yield increase in quality and efficiency.Breeding high yield,high nutritional cultivars and applying scientific fertilization management has become an important research direction for wheat in the Northwest Dryland.Rainfed conditions,identify the relationship between grain nutrient contents and yield formation and nutrient uptake and utlization,for providing theoretical basis and practical reference to breed new cultivars with high yield and high nutritional quality and optimize fertilizer application.This study was a three-year stationary field location experiment which was initiated in September 2013 to June 2016 in the Loess Plateau of China.There were 123 wheat cultivars from the main wheat areas in China were used as test materials.Plant samples were collected and measured during 2013-2016 at maturity.Analysis of biomass,yield formation factors and nitrogen?N?,phosphorus?P?and potassium?K?contents of different wheat cultivars and their relationship with N,P and K uptake and utilization.Main results were as follows:1.A significant negative correlation between N or P content and yield in high-yielding wheat.Grain yield was 6885.7 kg ha,and for every 1000 kg ha increase of grain yield,the grain N content was decreased by 3.2 g kg^-1,the grain P content was decreased by 0.4 g kg^-1.2.No significant differences in yield,spike number,grain number per spike and grain weight of different grain N content in high-yielding cultivar,and the high grain N?High-N?cultaver harvest index lower than the low grain N?Low-N?cultivar,about 4.4%.The yield,biomass,harvest index,spike number,and grain number per spike of High-N cultivar was more sensitive to fertilization than the Low-N cultivar.3.The High-N cultivar had higher grain P,lower grain K and higher vegetative part N than Low-N cultivar.The N content was 24.2 g kg^-1,the P content was 3.2 g kg^-1,and the K content was 3.7 g kg^-1 of the grain and the vegetative part N content was 7.0 g kg^-1 in the High-N cultivar.4.The N and P uptake in shoots of the High-N cultivar was higher than Low-N cultivar.and the increase of N,P and K in shoots of the High-N cultivar was higher than that of the Low-N cultivar after the fertilization.No significant differences in N and P translation to grain of different grain N cultivar,and the High-N cultivar K translation to grain was lower than the Low-N cultivar.N,P and K translation to grain of different grain N cultivar was reduced after fertilization.5.No significant differences in yield,spike number,grain number per spike and grain weight of different grain P content in high-yielding cultivar,and the High-P cultaver harvest index lower than the Low-P cultivar,about 4.3%.The yield,biomass,harvest index and spike number of High-P cultivars was more sensitive to fertilization.6.The High-P cultivar had higher grain N than the Low-N cultivar,no difference in grain K,and no significant differences in N,P and K of vegetative organs with different P contents.No difference in fertilization response.The N content was 23.4 g kg^-1,the P content was 3.3 g kg^-1 and the K content was 3.9 g kg^-1 of the grain in the High-P cultivar.7.The N and P uptake in shoots of the High-P cultivar was higher than Low-P cultivar.and the increase of N,P and K uptake in shoots of the High-P cultivar was higher than that of the Low-P cultivar after the fertilization.No significant differences in N and P translation to grain of different grain P cultivar,and the High-P cultivar K translation to grain was lower than the Low-P cultivar.N,P and K translation to grain of different grain P cultivar was reduced after fertilization.For breeding and cultivation of high-yield with high nutritional cultivars in dryland,the nutrient uptake and harvest index should be increased.N and P fertilizers should be applied rationally controlled based on the soil nutrient supply capacities,promoting uptake and utilization of N and P in grain,with the yield and nutrient contents of the grain can be increased,and realize the high-yielding and high quality wheat yield.