An approach to the screening index for low nitrogen tolerant wheat genotype

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(P0.01).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.