Effect of Nitrogen Fertilizer on Seedling Growth of Different Winter Wheat Genotypes with Different NUE

Four winter wheat genotypes of Xiaoyan128(low nitrogen use efficiency and low response),Shaannong78(low nitrogen use efficiency and high response),Xinong2208(high nitrogen use efficiency and low response) and Xiaoyan503(high nitrogen use efficiency and high response) were grown at different nitrogen levels in this study with genotype as main-treatment and nitrogen levels as sub-treatment.The content of chlorophyll(SPAD value),photosynthetic indexes and nitrate reductase activity(NRA) were measured at different stages of seedling development,the weight and total nitrogen content of shoot and root were also measured to study the physiology character of winter wheat genotypes with different nitrogen use efficiency and to provide a theory basis for cultivating high nitrogen use efficiency wheat genotypes.The results showed that under certain range of nitrogen level,SPAD value,NRA and photosynthetic rate increased with the increasing of nitrogen level and they increased significantly when treated with nitrogen than not.However,there were no significant differences between different genotypes at the same nitrogen treatment.