Light deficiency is a growing abiotic stress in rice production. However, few studies focus on shading effects on grain yield and quality of rice in East China. It is also essential to investigate proper nitrogen (N) application strategies that can effectively alleviate the negative impacts of light deficiency on grain yield and quality in rice. A two-year field experiment was conducted to explore the effects of shading (non-shading and shading from heading to maturity) and panicle N application (N_DP, decreased panicle N rate; N_MP, medium panicle N rate; N_IP, increased panicle N rate) treatments on rice yield- and quality-related characteristics. Compared with non-shading, shading resulted in a 9.5–14.8% yield loss (P<0.05), mainly due to lower filled-grain percentage and grain weight. N_MP and N_IP had higher (P<0.05) grain yield than N_DP under non-shading, and no significant difference was observed in rice grain yield among N_DP, N_MP, and N_IP under shading. Compared with N_MP and N_IP, N_DP achieved less yield loss under shading because of the increased filled-grain percentage and grain weight. Shading reduced leaf photosynthetic rate after heading, as well as shoot biomass weight at maturity, shoot biomass accumulation from heading to maturity, and nonstructural carbohydrate (NSC) content in the stem at maturity (P<0.05). The harvest index and NSC remobilization reserve of N_DP were increased under shading. Shading decreased (P<0.05) percentages of brown rice, milled rice, head rice, and amylose content while increasing (P<0.05) chalky rice percentage, chalky area, chalky degree, and grain protein. N_MP demonstrated a better milling quality under non-shading, while N_DP demonstrated under shading. N_DP exhibited both lower chalky rice percentage, chalky area, and chalky degree under non-shading and shading, compared with N_MP and N_IP. N_DP under shading decreased amylose content and breakdown but increased grain protein content and setback, contributing to similar overall palatability to non-shading. Our results suggested severe grain yield and quality penalty of rice when subjected to shading after heading. N_DP improved NSC remobilization, harvest index, and sink-filling efficiency and alleviated yield loss under shading. Besides, N_DP would maintain rice’s milling, appearance, and cooking and eating qualities under shading. Proper N management with a decreased panicle N rate could be adopted to mitigate the negative effects of shading on rice grain yield and quality.

光照不足是水稻生产中日益严重的非生物胁迫。然而，针对华东地区遮荫对水稻产量和品质的影响的研究却很少。研究适当的氮（N）施用策略也很重要，以有效减轻光照不足对水稻产量和品质的负面影响。通过为期两年的田间试验，探讨遮光（不遮光和从抽穗至成熟期间遮光）和穗施氮（N _DP，降低穗部施氮量；N _MP，中等穗部施氮量；N _IP，增加穗部施氮量）处理对水稻产量和品质相关特性的影响。与不遮荫相比，遮荫导致产量损失 9.5%~14.8%（P<0.05)，主要是由于灌浆率和粒重较低。不遮荫条件下N _MP、N _IP的产量高于N _{DP （} P <0.05），遮荫条件下N _DP、N _MP、N _IP水稻产量差异不显着。与N _MP、N _IP、N _DP相比由于增加了饱满粒百分比和粒重，因此在遮荫下实现了较少的产量损失。遮荫降低了抽穗后叶片光合速率、成熟期地上部生物量、抽穗至成熟期地上部生物量积累以及成熟期茎中非结构性碳水化合物（NSC）含量（ P <0.05 ）。_{遮荫下N DP}的收获指数和NSC再动员储备增加。遮荫降低了糙米、精米、整精米的百分比和直链淀粉含量（P<0.05），增加了垩白米百分比、垩白面积、垩白度和籽粒蛋白质（P< 0.05）。N _MP在无遮光下表现出更好的铣削质量，而 N _DP在阴影下演示。_{与N MP}和N _IP相比， N _DP在不遮荫和遮荫条件下的稻米白垩率、白垩面积和白垩度均较低。遮光下的N _DP降低了直链淀粉含量和分解，但增加了谷物蛋白质含量和挫折，从而导致与非遮光下相似的整体适口性。我们的结果表明，抽穗后进行遮荫时，水稻的产量和品质会受到严重影响。N _DP提高了 NSC 的再动员、收获指数和库填充效率，并减轻了遮荫下的产量损失。此外，_NDP将在遮荫下保持大米的碾磨、外观、烹饪和食用品质。可以采取适当的氮肥管理，降低穗氮施用量，减轻遮荫对水稻产量和品质的负面影响。