Effect of N fertilization on N translocation of different winter wheat cultivars during grain filling period in sub-humid farmland ecologic system

A field experiment was carried out on a Hongyou soil located in the south part of loess plateau with annual precipitation being 632mm. Eight winter wheat cultivars, named NR 9405, 9430, Yanshi No.9, XiaoyanNo.6, Shan 229, Xinong 2208, Aifeng No.3 and Shang 188, were used as indicating crops to study the effects of N fertilization on nitrogen translocation at grain filling period. The results showed that there were no significant difference on nitrogen translocation (NT), nitrogen translocation efficiency (NTE) between different cultivars,however, nitrogen translocation efficiency on haulm and contribution of transfer nitrogen to grain (NCR) showed a significant variation between different cultivars (P0.05). Results also showed that N application had no effect on those index. NR 9405 had the highest NTE being 76.65%, while Shan 229 was lowest which was 66.82%. Nitrogen harvest index(NHI) of Shan 229 was the highest, followed by NR 9403, Aifeng 3, Xinong 2208, Yanshi 9, Shang 188, NR 9405 and Xiaoyan No.6 sequentially. There was a significant difference on NUE between different cultivars (P0.001), among which Yanshi 9 was the highest being grain 37.25 g/g N, and Xiaoyan No.6 was the lowest being grain 29.29g /g N. NHI and NUE was not changed with the N application. There was a significant negative correlation between N content in grain and NUE which indicated that it was impossible to increase NUE and grain nitrogen concentration simultaneously as to one variety.