Abstract: The experiment was employed with main plot of nitrogen fertilizer application rate(0,90,180 and 270 kg/ha respectively),sub-plot of cultivar(CF008,Zhengdan 958 and Jinhai 5 respectively),and studied the relationship of source and sink three summer maize cultivars.The objective to clear what was the limiting factor for grain yield of different cultivar under different nitrogen fertilizer application rate(N rate).The main results showed that the relationship of source and sink was harmonious under N rate 90-180 kg/ha for three summer maize cultivars.Percent transmission and Pn of middle and upper layer leaf were high,and LAI developmental dynamic were rational because of the even light distribution within canopy,moreover,population grain number,population grain weight,and grain quality were high under N rate 90-180 kg/ha.For premature senility cultivar CF008,the effect of N rate on the ratio of grain number to leaf area was not significant.For Zhengdan 958,the ratio of grain number to leaf area in maturity was improving with N rate increasing,and sink number was larger than source under N rate 270 kg/ha.So the limiting factor for grain yield was source under high N rate for Zhengdan 958.While Jinhai 5 was opposite,the ratio of grain number to leaf area in maturity was decreasing with N rate increasing,and source number was larger than sink when increasing N rate,so the limiting factor for grain yield was sink not source.

Key words: Summermaize, N rate, The relationship of source and sink

CLC Number: 

• S513