Abstract: Utilization traits of different types of rice, more tillers and smaller panicle variety Kongyu131 and less tillers and bigger panicle variety Longjing 21 were used in this study. Four base-tiller nitrogen to spike-grain nitrogen application ratios of 10∶0, 8∶2, 7∶3, 6∶4 were used with three N levels of 115, 138, 161 kg/ha. The results showed that the tiller number of plant population and the maximum tiller number of more tillers and smaller panicle variety Kongyu131 were more than those of less tillers and bigger panicle variety Longjing 21, with the increase of nitrogen supply level. Increase of the base-tiller nitrogen led to the increase of stem and tiller number in the population, and increase of the spike-grain nitrogen led to the decrease of peak seedlings number. Effect of nitrogen fertilizer postponing on stem and tiller number in the population under low nitrogen level was higher than that under high nitrogen level. With the increase of nitrogen rate, the highest stems number（THSN）, the highest tillers number （THTN）, tillers panicle number （TPN） and tillers panicle proportion （TPP） in populations of two rice varieties increased, but effective tiller number rate and panicle rate decreased. When the nitrogen application ratio was 7∶3, the less tillers and bigger panicle variety Longjing 21 had higher effective tiller number rate and panicle rate. Whereas the more tillers and smaller panicle variety Longjing131 had higher effective tiller number rate and panicle rate when the nitrogen application ratio was 8∶2. Under low nitrogen level, increase of spike-grain nitrogen application led to the decrease of population stem and tiller number of more tillers and smaller panicle variety, and further resulted in insufficient population spike. The suitable increase of spike-grain nitrogen application would be helpful for improving effective tillering rate and panicle rate of the less tillers and bigger panicle variety under middle and high nitrogen level.

Key words: rice（Oryza sativa L.）, cold region, nitrogen supply method, growth dynamics, panicle rate