Abstract: 【Objective】 The yield potential and mechanical grain harvesting quality of new spring maize varieties suitable for mechanical grain harvesting were comprehensively evaluated to provide theoretical basis for popularizing the new spring maize varieties suitable for mechanical grain harvesting in Tumochuan Plain irrigation area.【Methods】 A total of 11 new spring maize varieties were selected,and the planting density was 105 000 plants/hm². The new spring maize varieties were evaluated from the aspects of growth period,plant traits,spike traits,grain water content at grain harvest,grain yield and mechanical grain harvesting quality,etc.,and were screened by bidirectional average plotting method.【Results】 There were significant differences in plant traits,spike traits,grain water content at grain harvest,grain yield and mechanical grain harvesting quality among the tested spring maize varieties（P<0.05）. The average growth period of the new spring maize varieties was about 130 days,all of them belonged to middle and late maturity varieties,and could be dehydrated by standing stalk after physiological maturity. The average grain water content of the 11 new spring maize varieties was 23.1% at grain harvest. The average yield of the new spring maize varieties was 14.28 t/hm²,and the yield of Lianchuang 825 was the highest,reaching 16.75 t/hm². When the grains were mechanically harvested,the breakage rate,impurity rate and yield loss rate of the new spring maize varieties were less than 5%,3% and 5%,respectively. Xinyu108,Lianchuang 825 and Qiangsheng 388 were selected by bidirectional average plotting method. These selected spring maize varieties had the characteristics of short growth period,low plant height and spike position,good grain setting,fast dehydration,high mechanical grain harvesting quality and great grain yield potential,etc..【Conclusion】 Xinyu 108,Lianchuang 825 and Qiangsheng 388 achieved high yield and high mechanical grain harvesting quality under the whole mechanized cultivation of dense planting. They had high density tolerance and high yield,and were suitable for mechanical grain harvesting. They were suitable for popularizing as mechanical grain harvesting maize varieties in Tumochuan Plain irrigation area.

Key words: Spring maize, Mechanical grain harvesting, Evaluation, Screening, Tumochuan Plain irrigation area