关键词: 水稻, 氮肥, 籽粒灌浆, 碾磨品质

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