Abstract: 【Objective】In order to seek the impacts of climate warming on growth process and yield of spring maize in recent 20 years in Northeast China, a study was conducted for providing a theoretical basis for food security.【Method】Three provinces (Heilongjiang, Jilin and Liaoning province) in Northeast China were selected for conducting regional research. Making use of the meteorological observation data and the long-term observation data of spring maize in recent 20 years in Northeast China, the relationships between climate factors (temperature and precipitation) and growth process and historical production data during growing season were analyzed by correlation and regression analysis and other statistical methods.【Result】It was found that the diurnal maximum temperature, minimum temperature and average temperature in Northeast China during spring maize growth season in 1989-2009 were rising significantly. Climate trend rates were 0.050, 0.045 and 0.044 ℃?a-1. During spring maize growth warming amplitude during the daytime was larger than the night. No significant change in the precipitation was found. During 20 years, the change tendency of spring maize average sowing date was 0.10 d in advance every year in experiment stations of Heilongjiang province, but the change tendencies were postponed in experiment stations of Jilin and Liaoning provinces, respectively, 0.18 and 0.21 d per year. The change tendencies of spring maize average maturity date were postponed in experiment stations of Heilongjiang, Liaoning and Jilin provinces, respectively, 0.39, 0.35 and 0.55 d per year. The change tendencies of spring maize average total growth days in Heilongjiang, Jilin and Liaoning provinces were an annual increase of 0.49, 0.17 and 0.34 d, respectively. The amplitude of the delayed maturity date was larger than the delayed sowing date, eventually resulting in increased number of spring maize growth days. The national varieties data and meteorological data correlation analysis in 1991-2006 showed that the rise of the diurnal maximum temperature (Tmax) in Heilongjiang extended national varieties growth period. The correlation between the state-approved varieties growth period and the diurnal maximum temperature (Tmax), minimum temperature (Tmin), average temperature (Tavg) in Jilin and Liaoning provinces showed a positive correlation. Analysis of the relationship between the growth period of the state-approved varieties and experiment station varieties by using T test showed that the growth days of them had a consistent increasing trend in Heilongjiang and Liaoning provinces, and the increasing trend had no significant difference. By adopting linear partial regression test method the importance of varieties and climatic factors on spring maize growth period was analyzed and the results showed that the extension of varieties growth period was the main factor causing experiment station varieties growth period prolonged. The average yield of spring maize showed an increasing trend, and the ascending order of the trend was Liaoning, Jilin and Heilongjiang provinces in recent 20 years. The farther north the yield increasing trend was greater, and the yield increase was more obvious. Panel data analysis showed that changes of the Tavg, Tmax and Tmin affected the yield of spring maize in prefecture-level city of Northeast China in 1989-2009. When the temperature rose, the yield in northeast significantly increased, especially in the Sanjiang plain area of the eastern Heilongjiang province, but the yield in southwest cities was obvious reduced in Northeast China.【Conclusion】Above evidences indicate that spring maize production is affected by climate warming in Northeast China. Spring maize varieties are gradually adapted to climate warming. Varieties improvement and sowing date adjustment for adapting climate warming can improve the yield of spring maize.

Key words: climate warming , spring maize , Northeast China , growth and development , yield , varieties growth period