| The study included two parts:(l) The incomplete diallel cross mating designs. The material were 13 new cultured waxy corn inbred lines and 91 crosses combined by 13 inbred lines. 91 crosses were made according to 2th Griffing's method to analyze general combing ability (GCA) and special combining ability (SCA). Quality characters were predicted by near infrared reflectance spectroscopy(NIRS) techniqe and chemic methods. (2)5 maize inbred lines as tester crossed with 18 waxy inbred lines according to NCII mating designs. 18 waxy inbred lines were studied by agronomic and economic traits observation analysis and cluster based on SSR markers.90 crosses were analyzed general combing ability (GCA) and special combing ability (SCA). The results as following:(l)In the incomplete diallel cross experimentation, GCA and SCA variance of ear length, sterile length, ear diameter, fresh-ear weight, rows per ear, kernels per row, kernels per ear, ear weight, axis weight, plant yield, 100-kernel weight, shelling percentage, unit weight, interval between anther and silk, plant height and ear height were significant at 0.01 level. Inbred line 6006, 6008, 6010 and 6016 had better comprehensive GCA of average plant yield and other traits contributing to plant yield. 6011 X 6019 had highest plant yield SCA and 6005x6017 had lowest one. Plant yield SCA variance ranged from 150.89 to 512.68, and inbred line 6008 and 6001 had largest and smallest variance respectively.At the aspect of quality characters,6007 had the heighest percentage of oil, protein and lysine, 6014 and 6016 had the heighest percentage of starch,6020 represented better percentage of oil and starch,6010 also was good at quality characters except of starch. The difference of amylopectin percentage in 13 waxy inbred lines was indistinct. According to the results of combinining ability and quality characters ,6016 and 6014 were fitted for industrial breeding. 6010 and 6006 were fitted for not only industrial breeding but also vegetable corn breeding. Other inbred lines had their own advantages and could be used in different breeding aims.(2 )The genetic distances (GD) of 18 inbred lines were calculated based on data of 16 traits. 18 inbred lines were classified into 5 groups: group I including 6001,6002,6008,6003, group II including 6004,6014,6019,6007,6017,6010,6020,6016,6006,6015, group III including 6005 and 6009,groupFV including 6011 and group V including 6013. To some degree, the cluster partly agreed with known pedigree, but there were some differences between them. The reason probably had connection with traits selection and interaction between traits and environment.(3) Genetic distances of 18 inbred lines were calculated based on SSR analysis data. In this cluster result, 18 inbred lines were classified 5 groups: group I including 6001, 6002,group II including 6003, 6004, 6005, 6017, group III including6011, 6020 , groupIV including 6006,6007,6014,6015,6016,6008,6009,6010 and group V including 6013 and 6019. The result approximately agreed with pedigree and previous researches, but there were still some difference.(4) Cluster analysis was taken by shortest distance method based on plant yield SCA as genetic distance. 18 inbred lines were approximately classified into 5 groups: group I including 6001,6016,6007,6010,6002,6008,6004, group II including 6003, 6013, 6009, groupIII including 6005 and 6017,groupIV including 6006,6015,6020,6014,6019 and group V including 6011. Cluster result of plant yield SCA partly agreed with pedigree, but there were some difference between them. The reason was deduced to be largely connected with interaction between gene and environment.(5) According to the results of three kinds of cluster analysis, analysis based on agronomic traits and SSR were easy to be influenced by environment and interaction between gene and environment, SSR cluster could not only eliminate environment influence, but also especially amplify DNA fragment connecting with yield trait, but SCA cluster was related with breeding programe close...
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