| Aiming at improving maize variety management, promoing breeding efficiency and level by clustering the heterosis groups correctly and setting up the correspondent hterosis pattern, we had made a systematic research on the maize hybrids germplasms in Sichuan Province. In the study the material were 22 maize inbred lines from Sichuan and 136 crosses combined by 17 new inbred lines. The 136 crosses were made according to 4th Griffmg's method to analyze general combing ability (GCA) and special combing ability (SCA). The 22 inbred lines were studied by agro-economic traits observation analysis and cluster based on SSR markers, AFLP markers and SCA. The main results are followed.(1) The results of combining ability analysis indicated that, among the 17 studied inbred lines, inbred line 9636, 20FS207, HZ106-3 and yuzong\5BC-2 performed better judged by high plant yield, high plant yield SCA and wide variance range of plant yield SCA, and high plant yield crosses could probably be created by the them. Especially inbred line 9636 and 20FS207. they had advantages to create big-ear high yield crosses. They are very useful for commercial breeding at present.(2) The genetic distances (GD) of 22 inbred lines were calculated based on data of 15 agro-economic traits. The 22 inbred lines could be classified into 5 groups and 7 sub-groups based on the GD: sub-group 1-1 including 18-599, 9636, 971-18, sub-group 1-2 including Yuzong\5BC-2^ 20FS207, Da?40, sub-group 1-3 including 02S4172-1, 975-11; group 2 including 95220-4, 99S2041-1-1, 975-12: group 3 including 698-3, 99S2052-31, 5003, 9614, 01S5205-2, B73; group 4 including 02S4101-1 ,HZ106-3,Mol7; group 5 including 478 and Huangzaosi. To some degree, the cluster partly agreed with known pedigree, but there were some differences between them. The reason probably was the traits selection and the interaction between traits and environment.(3) Cluster analysis was taken by shortest distance method based on plant yield SCA as genetic distance. 17 inbred lines were approximately classified into 4 groups and 7 sub-groups: sub-group 1-1 including 18-599, 02S4172-K 9636, 01S4101-1, sub-group 1-2 including 971-18, 20FS207; sub-group 2-1 including 698-3, 975-12, 99S2052-31, sub-group 2-2 including 99S2041-1-1, 01S5205-2, 478; sub-group 3-1 including Yuzongl5BC-2, sub-group 3-2 including 95220-4, 975-11, HZ106-3; group 4 including 9614. The cluster result of plant yield SCA partly agreed with pedigree, but there were some difference between them. The reason probably was the interaction between gene and environment.(4) Genetic similarity (GS) of 22 inbred lines were calculated based on the data of SSR analysis. Although the average GS (0.6348) was bigger, wider GS range (from 0.5372 to 0.9149) showed higher genetic polymorphism among studied materials. In this cluster result, 22 inbred lines were classified into 7 groups and 9 sub-groups:group 1 including ?a?40; sub-group 2-1 including B73, 478 , 5003, 975-11, sub-group 2-2 including Mo 17; group 3 including 9614, 99S2041 -1 -1, 01S5205-2, 95220-4 and HZ 106-3; sub-group 4-1 including Huangzaosi, sub-group 4-2 including 971-18, 20FS207; group 5 including 9636; group 6 including 975-12, 99S2052-31, 698-3; group 7 including 18-599, Yuzong\5BC-2, 02S4172-1, 02S4101-1. The result approximately agreed with pedigree and previous researches, but there were still some difference.(5) Genetic similarity (GS) of 22 inbred lines were calculated based on the data of AFLP analysis. The GS ranged from 0.6099 to 0.9725 with an average 0.7678. In this cluster result. 22 inbred lines were classified into 8 groups: group 1 including Z)a?40; group 2 including B73, 478, 5003, 975-12, 99S2041-1-1, 01S5205-2, 95220-4, 9614, 975-11, HZ106-3, 99S2052-31, 698-3, 02S4172-K 02S4101-1; group 3 including Mol7, Yuzongl5BC-2; group 4 including 20FS207: group 5 including 9636; group 6 including 18-599; group 7 including 971-18: group 8 including Huangzaosi. The result approximately agreed with pedigree and previous researches, but there were still some...
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