Effects Of Nitrogen Fertilizer On Yield And Nitrogen Utilization Of Hybrid Rice

Yield and nitrogen use efficiency are two major factors restricting the development of hybrid rice.It is of great significance,for reduce nitrogen pollution and ensure high yield,to explore the relationship between rice yield and n itrogen utilization traits and to screen out high-yielding materials under various nitrogen levels.Combining ability of yield and nitrogen physiological utilization rate related traits of hybrid rice were analyzed using incomplete diallel cross of five high combining ability sterile lines(Zhe 8010 A,Yixiang 1A,Chuannong 1A,Gang 46 A,and 803A)and six restorers(Chenghui 727,Mianhui 662,Mianhui 4761,Yahui 2115,Lehui 188,and Yihui 1577),with low,medium and high nitrogen levels.Experimental results showed that the interaction between sterile lines and restorer lines affected the yield and nitrogen utilization traits at various nitrogen levels.Under low nitrogen level,yield combining ability of Lehui 188,Chenghui 727 and 803 A,specific combining ability(SCA)of Yixiang 1A × Yahui 2115,Chuannong 1A × Chenghui 727 and 803 A × Mianhui 4761,yield of Gang 46 A × Lehui 188,physiological nitrogen utilization of Yixiang 1 A × Yihui 1577 and nitrogen harvest index(NHI)of Zhe 8010 A × Mianhui 662 were optimized.By contrast,under high nitrogen level,yield combining ability of Zhe 8010 A,Yixiang 1A,Mianhui 662 and Yahui 2115,SCA of 803 A × Mianhui 662,Zhe 8010 A × Yahui 2115 and Yixiang 1A × Chenghui 727,yield of Zhe 8010 A × Yahui 2115,physiological nitrogen utilization and NHI of Gang 46 A × Yihui 1577 were best.Moreover,yield combining ability of Mianhui 4761,Chuannong 1A,Lehui 188,SCA of Zhe 8010 A × Chenghui 727,Yixiang 1A × Yihui 1577 and Gang 46 A × Mianhui 4761,yield of Gang 46 A × Mianhui 4761,physiological nitrogen utilization of Yixiang 1A × Yahui 211 and NHI of Zhe 8010 A × Yahui 2115 were highest under normal nitrogen level.The yield traits of Gang 46 A × Mianhui 4761 and 803 A × Mianhui 4761 were significantly higher than Gangyou 188.At different nitrogen levels,the nitrogen accumulation and utilization characters and the yield traits general combining ability effect of the same parent were quite different.Different nitrogen levels had a significant effect on the nitrogen accumulation and utilization traits and yield traits of each parent.The correlation between yield and nitrogen harvest index was not significant,and the yield was negatively correlated with nitrogen physiological utilization rate.Therefore,suitable nitrogen levels should be used when breeding combination of high quality and yield hybrid rice in different fertility conditions.