In order to study the mechanisms of reducing grain weight of Rht10,a dormant dwarfing gene in Triticum aestivum,two near isogenic lines,Lumai 15 and Rht10 Lumai 15 were selected as experimental materials and the dynamic changes of grain weight during grain filling stage were measured and analyzed by Logistic equation fitting.The results showed that the grain weight of the two lines showed “S”shape curve;the grain weight of Rht10 Lumai 15 was always lower than that of Lumai15,and the decreasing amplitudes were between 1.17% and 35.70%.The changes of grain filling rate showed a single peak curve,and the grain fill-ing rate in Rht10 Lumai 15 was higher than that in Lumai 15 during the middle stage.The results of Logistic equation fitting showed that compared with Lumai 15,the appearance of maximum grain filling rate in Rht10 Lumai 15 was advanced with 1.57 days;the maximum grain filling rate was 0.26 g per 100 grains one day higher;the grain filling duration was 10.08 days shorter,and the active growing duration was 11.12 days shor-ter.The duration of middle and later stage of grain filling in Rht10 Lumai 15 was obvious shorter than that in Lumai 15.Thus,the effects of Rht10 on grain weight were involved in the whole grain development duration. The gene increased the maximum grain filling rate and grain filling period,especially the middle and late peri-od,which might result in the reduction of wheat grain weight.%为了探究显性矮秆基因 Rht10降低粒重的原因，本研究以 Rht10鲁麦15、鲁麦15近等基因系为材料，分析其籽粒形成期粒重的变化，并利用 Logistic 方程拟合灌浆过程。结果显示，在籽粒形成过程中，二者粒重的变化均呈“S”型曲线，但 Rht10鲁麦15粒重均低于鲁麦15，降低幅度在1．17％～35．71％之间；灌浆速率的变化均呈单峰曲线，灌浆中期 Rht10鲁麦15的灌浆速率明显高于鲁麦15。Logistic 方程拟合结果表明，与鲁麦15相比，Rht10鲁麦15的最大灌浆速率出现时间提早1．57 d，最大灌浆速率高0．26 g／（百粒·d），籽粒灌浆期短10．08 d，灌浆活跃持续天数短11．12 d，灌浆中期、后期的时间明显低于鲁麦15。由此可见，Rht10基因对粒重的影响贯穿于籽粒发育的整个过程。该基因提高了灌浆期的最大灌浆速率，但缩短了灌浆时间，尤其是缩短了灌浆中期、后期的时间，造成粒重降低。
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