Abstract:Screening and breeding low nitrogen(N) tolerant wheat genotype is one of the effective alternatives to alleviate pollution of environment,and increase the utilization efficiency of N fertilizer.A simple and scientific screening index plays an important role in the screening and breeding program.In this study,a hydroponic experiment and a field trial were carried out to screen the index for low N tolerant wheat genotypes under N stress and normal N supply condition,respectively.Results showed that total dry weight showed a significant genotypic variation at both normal and low N supply(the CV was 18.21%and 29.03%,respectively).Relative dry weight(low N supply/normal N supply) also showed a significant genotypic variation(CV was 22.73%).Correlation analysis showed that relative dry weight was highly significantly correlated to relative plant height,relative total N uptake,and relative N utilization efficiency(P<0.01).The relative total dry weight of wheat in solution culture system was significantly correlated to the relative grain yield(minus-N/plus-N) in field trial(r=0.77**,n=12).Therefore,relative total dry weight at seedling stage would probably be an effective screening indexfor screening wheat genotype which tolerant to low N.