| Genetic diversity and heterotic grouping among maize germplasm are always fundamentally important in maize breeding. To define heterosis group and heterotic patterns,it is tremendously significant for improving the efficiency in maize breeding. Construction of DNA fingerprints will provide a basis for distinguishing truth of breed and protecting the property of maize variety. In this study, SSR molecular markers and morphological markers were made to study the genetic diversity in 82 maize inbred lines, and Zhenghong series hybrids and their parents were constructed DNA fingerprints database. The main results of study were summarized as follows:1. The results of analysis of 15 phenotypic characters showed that genetic distances among the 82 inbred lines ranged from 9.05 to 146.23, with an average of 50.57. The average of genetic distances were greater, and the ranges of variation were wider.It indicated that the genetic diversity of these inbred lines was ample. Cluster analysis indicated that all the inbred lines could be divided into six groups, Clusterâ… includes 27 inbred lines with 32.9 percent of all inbred lines, Clusterâ…¡includes 19 hybrids with 23.2 percent of all inbred lines, Clusterâ…¢,â…£, andâ…¤include 1,3, and 2 inbred lines with.1.2 percent,3.7 percent, and 2.4 percent of all inbred lines, Cluster VI includes 30 inbred lines with 36.6 percent of all inbred lines. The result of clustering by morphological markers was bad consisted with family tree.Cluster analysis was carried out based on the 15 characteries, and the results reflected the differences of comprehensive traits in the most part which couldn't reflect the genetic relationship comprehensively and accurately.It indicated that the reliability of using morphological markers to study the genetic diversity was lower.2. The polymorphisms were investigated by 216 pairs of SSR primers, and 63 primers with stable amplification profiles were selected to study the genetic diversity of 82 maize inbred lines.63 pairs of SSR primer distributed on the ten chromosomes of maize produced stable amplified bands and 601 alleles were detected among the maize inbred lines. The average number of alleles per locus was 9.5 with a range from 4 to 24. The values of polymorphism information content (PIC) for each SSR locus varied from 0.5179 to 0.9256 with an average of 0.7826. The genetic similarities of SSR marker pattern among the 82 maize inbred lines ranged from 0.5441 to 0.9334 with an average of 0.6673.3.82 inbred lines were divided inio seven groups by UPGMA (Unweighted Pair Group Method Agrithmetic Average) according to genetic similarities based on SSR markers:some inbred lines belonges to five familiar groups occupied 84.1 percent, of which belonged to Reid group occupied 32.9 percent, belonged to PB group occupied 23.2 percent, belonged to Lancaster group occupied 13.4 percent, belonged to Tangsipingtou group occupied 7.3 percent, belonged to Lvdahonggu group occupied 7.3 percent. The other inbred lines divided into two groups which occupied 11.0 and 4.9 percent. The result meant there were biggish diversity between these groups and other five groups.The pedigree of some kown inbred lines were analyzed.The result of clustering by SSR were well consisted with family tree. Several parents of registered maize hybrids were analyzed combining with the results of germplasm cluster.4. In the study, fingerprints were established for Zhenghong series Hybrids and Their Parents by SSR marker. Zhenghong series hybrids and their parents were used to screen several SSR primers and finally a set of primer pairs fitting establishing DNA fingerprinting were conformed, which were used in building DNA fingerprinting database of Zhenghong series hybrids and their parents. The main results were as follows:10 maize inbred lines were analyzed by using SSR.15 pairs SSR primers were selected to give polym orphic, stable and repeated amplification profiles. Six primers including phi057, umc1380, phi063, umc1061, umc1196, bnlg278 were selected to build DNA fingerprinting database of all 10 inbred lines. DNA fingerprint map of 9 maize hybrids were built with 13 pairs SSR primes. These primers also gave polymorphic,stable and repeated amplification profiles. Six primers including phi064, phi101049, phi034, phi328175, umc1228, bnlg1237 were selected to build the DNA fingerprinting database of all 9 maize hybrids. The results indicated that the SSR technique was practical and effective to identify the reality of maize hybrids and their parents.
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