Abstract: 【Objective】The objectives of this study were: 1) to assess the breeding potential of maize populations including 2 of tropical origin and 7 of temperate origin; 2) to find a new heterotic pattern among the 9 populations. 【Method】 A 9-parent diallel was formed by Griffing IV and 36 crosses were obtained. The populations per se and crosses were evaluated in two different environments (Anyang of Henan Province and Shiyan of Hubei Province) during 2002-2003. Data for ear length (EL), number of rows per ear (RPE), number kernels per row (KPR), a hundred- kernels weight (HKW), ratio of kernels weight to the ear weight (RKW) and plot-kernels weight (PKW) were analyzed using a mixed (AD) model and MINQUE(1) methods; The heritability and genetic variance components for EL, RPE, KPR, HKW, RKW and PKW were estimated. The additive genetic effects for the populations and dominance genetic effects for the crosses were calculated. 【Result】The parameters for almost all the traits concerned across the environments showed significant (P≤0.05) or highly significant (P≤0.01). Considering PKW that the ratio of genetic variance components to total variances are ranked as dominance > dominance  environment > additive  environment > additive; The estimated of narrow sense heritability are sequenced as RPE > KPR > EL> RKW > HKW > PKW. Concerning the additive and dominance effects for PKW that the top 4 populations are 1 (Suwan1), 6 (Stay green c4), 5 (WBM C4) and 9 (Zhongzong4), while the best 4 crosses are graded as 3×6 (BSSS C9×Stay green C4) >1×3(Suwan1×BSSS C9) >1×2(Suwan1 ×BS16) > 6×7(Stay green C4×Liaolü population). 【Conclusion】This study provided helpful information for utilizing exotic germplasm in temperate breeding program, Suwan1 and Stay green c4 are very promising exotic germplasm, which with BSSS C9 must be performing a powerful heterotic pattern. Furthermore, it is useful in practical breeding to make a combination between Suwan1 and Stay green c4, which performs a new heterotic pattern with BSSS C9 between tropical and temperate maize germplasm. Reciprocal recurrent selection (RRS) scheme should be used in the future.