Abstract: To explore the relationship between kernel weight, grain filling parameters and meteorological factors, three maize varieties (early maturing variety Demaiya 1, medium maturing variety Jidan 27 and late maturing variety Zhengdan 958) were selected for a sowing date experiment in Harbin in 2017-2018. We analyzed the kernel development dynamics and grain filling characteristics. There was a significant positive correlation between yield and kernel weight (P<0.01), but no correlation between yield and kernel number per ear. Kernel weight was significantly positively correlated with grain filling rate (P<0.05), but not correlated with the time of reaching maximum rate and active period. The accumulated temperature, radiation, and saturated water pressure values were significantly positively correlated to filling rate (P<0.01). Increases in temperature and radiation in the early stage contributed to the increase in the filling rate of the earlymaturing variety, while decreases in temperature and radiation in the later period significantly reduced filling time and filling rate of the latematuring variety. Kernel weight was negatively correlated with precipitation after anthesis and positively correlated with radiation. The relationship of kernel weight with accumulated temperature varied across maize variety. Accumulated temperature was the major factor influencing kernel weight. Maximum grain weight would be obtained when the accumulated temperature of early, middle, and late maturing varieties reaches 920, 1020, and 1100 ℃ respectively.

Key words: meteorological factor, maize, yield, grain filling, cold region.