Differences in yield，nitrogen accumulation and utilization of different genotypes of hybrid rice

In order to study the differences of yield，nitrogen accumulation and utilization of different genotypes of hybrid rice under different nitrogen application rates，Yixiangyou 2115，Yixiangyou 1577，Gangyou 188 and Gangyou 1577 were used as materials under the levels of low nitrogen，normal nitrogen and high nitrogen fertilizer. The results showed that yield，nitrogen accumulation and utilization of four hybrid rices were all controlled by the interaction effect of variety and nitrogen fertilizer level. At the normal nitrogen level，the yield and nitrogen harvest index of Yixiangyou 2115 were at the highest level，and its nitrogen use efficiency was high at normal nitrogen application level. Yixiangyou 1577 had the highest nitrogen harvest index and higher yield at the low nitrogen level， and its nitrogen use efficiency was high at low nitrogen level. Gangyou 188 had the highest yield and nitrogen harvest index at high nitrogen level，and its nitrogen use efficiency was high at the high nitrogen level. Gangyou 1577 had the highest nitrogen harvest index and high yield at high nitrogen level，and its nitrogen use efficiency was high at high nitrogen level. The yield of four hybrid rice varieties were most affected by nitrogen harvest index at different nitrogen fertilizer levels. Therefore，nitrogen use efficiency of different hybrid rice varieties had different suitable levels of nitrogen，rice variety should be chosen carefully in the ecological areas of different fertility levels.