The difference of nitrogen uptake and utilization in waxy corn III.Genetic differences in nitrogen distribution and translocation

In order to understand the regularity of nitrogen(N)distribution and translocation and their effects on N absorption and utilization,explain the genotypic differences of N distribution and translocation and their effects on the yield formation,31 waxy corn(Zea mays L.ceratina Kulesh)varieties released in recent years in China were selected to analyze their characteristics of N distribution and translocation under same nitrogen fertilization condition.The results showed that the N distribution centre changed with the shift of the growth centre.N mainly distributed in leaf and culm before silking stage,then the N distribution centre transferred to ear after silking stage,and then transferred to kernel formation gradually.Moreover,there were significant differences of N translocation rate and its contribution on production in different organ among different varieties,respectively.Correlation analysis showed that N translocation rate primarily affected on yield,N utilization efficiency and N harvest index,but it had slight effect on total N.Path analysis showed that N translocation rate of culm was higher for the high fresh ear yield varieties,while the N translocation rate of culm and tassel was higher for the high fresh kernel yield varieties,and the N translocation rate of leaf,bracteal leaf and ear axis was higher for the high kernel yield varieties.In addition,higher N translocation rate of leaf had a beneficial effect on N utilization efficiency as for fresh ear,fresh kernel or maturity kernel of the produce of waxy corn.Six varieties,Feng nuo 2146,Jing ke nuo 267,Hu yu nuo 3,Jing ke nuo 218,Qian nuo 668 and Jing ke nuo 2000,were classified as high yield and high N utilization efficiency among 31 waxy corn varieties,with an average N translocation rate of 25.53% in the fresh ear stage,and an average N translocation rate of 47.60% in the maturity stage,which were 27.48% and 22.94% higher than that of other varieties,respectively.In addition,the average N harvest index in the fresh ear stage and the maturity stage were 0.35 and 0.62,which were 8.43% and 9.90% higher than that of other varieties,respectively.