氮肥后移对杂交籼稻产量及不同粒位稻米垩白与食味品质的影响

以低垩白高食味品种宜香优2115和高垩白低食味品种F优498为材料,在施氮量150 kg/hm²条件下,研究了3 种氮肥运筹方式（基肥:蘖肥:穗肥分别为5:3:2、3:3:4、3:1:6,分别记为N1、N2 N3）和不施氮（N0）对杂交籼稻产量及不同粒位稻米垩白性状和食味品质的影响,并探讨了不同粒位稻米垩白性状与食味品质的关系。结果表明,品种、氮肥运筹对产量、氮肥农学利用效率及不同粒位稻米垩白性状及食味值均存在显著影响。参试2个品种产量及氮肥利用效率均以N2处理最高,实现了产量及氮肥利用效率的协同提高;同时能进一步降低宜香优2115不同粒位的垩白性状、提高相应粒位食味值;而F优498的食味值以N1处理为宜,可改善其不同粒位稻米品质。进一步分析发现,垩白度和垩白粒率强势粒低于弱势粒、一次枝梗上的籽粒低于二次枝梗上的籽粒、穗上部籽粒低于穗中部和下部籽粒,而食味值则强势粒高于弱势粒、一次枝梗上的籽粒高于二次枝梗上的籽粒、穗上部籽粒高于穗中部和下部籽粒。相关分析表明,稻米垩白性状与食味值呈显著或极显著相关（r=-0.706^*~-0.937^**）,降低稻米垩白是提高食味品质的主要途径。

Effects of Postponing Nitrogen Topdressing on Yield,Chalkiness in Different Grain Positions and Tasting Quality of Hybrid Indica Rice

The low chalky with high-tasting variety Yixiangyou 2115 and the high chalky with low-tasting variety F You 498 were used as the test materials, and three nitrogen fertilizer management methods （basic fertilizer: tiller fertilizer: panicle fertilizer ratios were 5:3:2, 3:3:4, 3:1:6, respectively, denoted as N1, N2, N3） under the condition of nitrogen application rate of 150 kg/hm², and no nitrogen （N0） were set up, the effects of nitrogen fertilizer management methods on the yield, chalkiness and taste quality of hybrid indica rice, and the relationship between the chalkiness and tasting quality in different grain positions were studied. The results showed that the varieties and N fertilizer management had significant effects on grain yield, nitrogen agronomic use efficiency, rice chalkiness and tasting value of different grain positions. The yield and nitrogen use efficiency of the two tested varieties were the highest with N2, achieved a synergistic increase in yield and nitrogen fertilizer use efficiency. At the same time, it could reduce the chalkiness and increase the taste value in different grain positions of Yixiangyou 2115. However, F You 498 should be treated with N1, which could improve its grain quality in different grain positions. Further analysis found that the chalkiness and the chalky grain rate of the superior grains were lower than the inferior grains, the grains on the primary branches were lower than the grains on the secondary branches, the grains in the upper of the panicle were higher than those in the middle and lower panicle. The taste value of the superior grains was higher than the inferior grains, the grains on the primary branch was higher than the grains on the secondary branch, and the grains in the upper of the panicle were higher than the grains in the middle and lower of the panicle. The correlation analysis showed that the chalkiness was significantly or extremely significantly correlated with tasting value （r=-0.706^*~ -0.937^**）. Reducing the chalkiness of rice was the main way to improve tasting quality.