A Study On Nitrogen Nutrient Variance Of Different Maize Genotypes Under Nitrogen Stress

In the research, 66 maize genotypes were studied by hydroponics experiments. The criterion was chosen in order to select different nitrogen efficient maize genotypes. The criterion was the ratio of maize dry weights whose no nitrogen to normal nitrogen treatments. If the value is over or equal to 0.50 then the genotype was high nitrogen efficiency genotype. If the ratio lower or equal to 0.10 then the genotype was low nitrogen efficiency genotype. The other were middle nitrogen efficiency genotypes. According to this, there were 7 high nitrogen efficiency genotypes and 7 low nitrogen efficiency genotypes respectively.Pot experiments were made to study the accumulation and distribution of nitrogen in plant. The results were as follows. First, nitrogen content in different efficiency genotypes in seedling were little different under nitrogen stress. Second, during whirling stage, the transfer efficiency of nitrogen from old part to new part under nitrogen stress in high efficiency genotypes. And the nitrogen content in stem was lower than low nitrogen efficiency genotype that made the transfer effect was high. Third, in tassel period, under nitrogen stress, in high nitrogen efficiency genotype the transfer efficiency of nitrogen was higher than low efficiency genotype from lower leaves to tassel or middle leaves. Last, in mature stage, nitrogen transfer of nitrogen from plant to seed in high nitrogen efficiency genotype was more quickly than low efficiency genotype.The field experiments indicated that the yield of high efficiency of maize was higher than low efficiency genotype.It is obvious that, the criterion in this study could be the index of selecting high efficiency genotypes in maize.