Abstract: To explore the relationship between grain filling of chalky rice, milling quality and the nitrogen (N) fertilizer topdressing of panicle, the rice cultivar OM052 with high grain chalkiness was as material, and panicle N fertilizer applied treatment and no N panicle fertilizer treatment were set. The dry matter production, dynamic characteristics of grain filling and rice milling quality to different N treatments were investigated. The results showed that: applying N fertilizer consistently increased the amount of dry matter accumulation from heading to maturity, enhanced the initial filling power (R0), maximum filling rate (Gmax) and average filling rate (Gmean) of the spikelets, advanced the occurrence time of the Gmax with 0.95 d, but shortened the duration of grain filling with 0.69 d. By contrast, under no N fertilizer topdressing, the R0, Gmax and Gmean of the spikelets were consistently reduced, and the rates of grain filling were slowly decreased after reaching the Gmax, thus the grain filling period was prolonged. Moreover, the application of panicle N fertilizer increased the rates of brown rice, milled rice and head rice by 1.46%, 2.52% and 3.57%, respectively, which improved milling quality of rice. There were significant positive correlations between the amount of dry matter accumulation from heading to maturity, Gmean, Gmax and rice milling quality, while significant negative correlations between the time of Gmax occurrence, active grain filling period and rice milling quality. The synergistic optimization of grain filling characteristic parameters was beneficial to guarantee the production of photosynthetic substances from heading to maturity, and improve the milling quality of rice.

Key words: rice, nitrogen fertilizer, grain filling, milling quality

摘要： 为明确垩白籽粒灌浆特性与稻米加工品质的关系及氮素穗肥调控效应，以高垩白水稻OM052为材料，设置追施氮素穗肥和不追肥处理，分析其物质生产、灌浆动态特征、加工品质及其对氮素穗肥的响应。结果表明：追施氮素穗肥显著增加了抽穗至成熟期的干物质积累量，提高了籽粒灌浆的起始生长势，灌浆启动提早、平均灌浆速率和最大灌浆速率增加，最大灌浆速率出现时间提前0.95 d，但活跃灌浆期缩短0.69 d。未追施氮素穗肥处理的籽粒灌浆启动滞后，灌浆速率小，且在达到最大灌浆速率后下降平缓而灌浆时间延长。追施氮素穗肥条件下稻米的糙米率、精米率和整精米率显著提高1.46%、2.52%和3.57%，加工品质得以改善。抽穗至成熟期的干物质积累及平均灌浆速率和最大灌浆速率分别与加工品质呈显著或极显著正相关，达到最大灌浆速率时间和活跃灌浆期与加工品质呈显著负相关。在保障抽穗至成熟期光合物质生产的基础上，协同优化籽粒灌浆特征参数有利于改善稻米的加工品质。

关键词: 水稻, 氮肥, 籽粒灌浆, 碾磨品质