Wheat Varieties Growth And Yield Response Characteristics Of Different Nitrogen Levels

Breed improvement and progress of cultivation techniques are the primary causes of continuous improvement of wheat yield.In order to explore the potential yield wheat varieties and improved varieties orientation,we should select high-yielding varieties and establish relevant cultivation techniques.In this study,the representative wheat varieties of the 1960s,1980s,21st century,respectively,were used as materials.We set up different nitrogen levels via field experiment,and analyzed the impact of nitrogen fertilizer on yield and nitrogen use efficiency of six wheat varieties of three years systematically.The results defined the regulation of different fertilization to photosynthesis,nitrogen metabolism and material production of wheat varieties from different years,and these research results intended to provide evidence of efficient management of high-yield wheat varieties cultivated and wheat breeding direction.The main findings are as follows:1.Growth response characteristics of wheat varieties from different years in different nitrogen content.1)During the wheat growth process,changes in the number of tillers can reflect the quality of the accumulation of population and spike formation.1960s varieties has more tillers in the heading and flowering stage,while 1980s and 2000s in maturity,which indicated 1980s and 2000s have less consumption in early and higher fertility late spike rate in late growth stage.As nitrogen using rate increasing,tillers of 1980s and 2000s variety increased.Under the N225 treatment,1960s variety has most tillers.With the amount of nitrogen increasing leaf area index of 1960s varieties showed a downward trend,while 1980s and 2000s variety showed up-regulation trend,which indicated 1980s and 2000s had more efficient using rate of nitrogen fertilizer.As amount of nitrogen increasing plant height of 1960s varieties improved,which was higher than the 1980s and 2000s significantly.Under low nitrogen treatment 1980s varieties reached the maximum height,While 2000s under N225 treatment,which showed that as time goes by,reducing the height and getting rid of nitrogen are good ways to breed improvement.2)Response characteristics of photosynthetic characteristics of wheat varieties from different years in different nitrogen treatments.1980s and 2000s of flag leaf varieties reached a maximum at N225 treatment in the late wheat growth performance.For 1960s,variety regularity of net photosynthetic rate was not strong,which reached maximum at N150 and N375 treatment in flowering and grain filling stage,respectively.These indicated that modern varieties were more stable and had more rational use of nitrogen fertilizer.SPAD content in leaves of different varieties had reached the peak from 7 to 14 d,and it was the highest under N375 treatment,then the N225 treatment,with N150 treatment last.In blade filling stage of 1980s and 2000s variety the ability of keeping green was stronger than 1960s varieties,which could make more dry matter accumulation after flowering.2.Response characteristics of yield and yield wheat varieties in different years under different nitrogen treatment.Dry matter accumulation of 1960s was lower than 1980s and 2000s varieties in the late growth stage,probably because the post-acceleration of the accumulation rate failed to compensate the lack of pre-ruomiao which was root in slow rate of dry matter accumulation in early growth stage.At N225 and N375 treatment,two varieties of had little difference in dry matter accumulation,which indicated that two varieties of 1980s were mainly through its own population to adjust to the dry matter accumulation rather than depending on nitrogen fertilizer in late growth stage.The overall rate of dry matter accumulation of 2000s was relatively uniform throughout the growing period.From flowering to maturity,groups dry matter accumulation of 1960s was less,which showed that during evolution wheat varieties pay more attention to adjust the rhythm wheat dry matter accumulation,and tend to improve plant growth conditions of early growth stage to accumulate productive of the late growth stage that had more efficient use of landffertilizer and light energy,rather than increasing the seeding rate which cost more,.Under three N treatments of N150,N225 and N37,effective panicle varieties increased with nitrogen rate increasing,while grain number and grain weight showed a downward trend.Effective panicle and grain number of 2000s varieties were significantly higher than the 1960s and 1980s variety,but the grain weight of 1980s was the highest.The results showed increasing of effective panicle and grain number\and reducing grain weight are mainly direction of improved varieties in recent years.Yield of wheat varieties exhibited the trend from increasing to decreasing with nitrogen improving.All varieties reached the highest production level in the nitrogen rate 225 kg/hm2.When in the same nitrogen using level,2000s wheat yield was significantly higher than 1960s and 1980s.the affection of different years varieties,nitrogen level and interaction on wheat yields was significant.3.The absorption and utilization of wheat varieties in different nitrogen levels.Nitrogen content of leaves,stems and glumes of wheat varieties from different years in flowering stage increased with the nitrogen gradually increasing.The nitrogen content of leaf and stem under N375 treatment was significantly higher than N150 and N225 treatment.The result indicated increasing the amount of nitrogen fertilizer will help to improve the nitrogen content of vegetative organs in flowering stage.When in maturity stage,nitrogen content of 2000s cultivars under N150,N225,N375 treatment was highest,which showed modern varieties were more favorable to grain nitrogen accumulation,and had a higher nitrogen fertilizer use efficiency.In the same nitrogen treatment,2000s had more efficient use of nitrogen nutrient than the other varieties,which could promote grain dry matter accumulation.Affection of wheat varieties from different years,nitrogen levels and interaction between the two partial was very significant to productivity.