Abstract: 【Objective】To improve the utilization efficiency of maize backbone inbred lines in hybrid parents.【Methods】Genetic diversity analysis and stem rot resistance identification of 43 maize backbone inbred lines and 11 reference lines were carried out by SSR molecular markers,cluster analysis and field inoculation methods.【Results】A total of 242 alleles were detected in 43 maize backbone inbred lines using 40 pairs of universal SSR primers,with an average of 6.05 alleles per pair of primers and an average of 0.61 polymorphism information. UPGMA cluster analysis showed that 43 backbone inbred lines and 11 reference lines were divided into 7 heterophytic groups,among which M17Y130,MU6,M18N41,M17Y334,M85Z,MU7 and M17Y340 were isolated and tentatively classified as M group. The genetic diversity of 43 backbone inbred lines was analyzed and the field resistance of stem rot（Fusarium graminis） was identified. Among them,37 backbone inbred lines were resistant to stem rot,mainly from Lüda red bone group,Foreign Reid group and P group,accounting for 86.05%. The resistance of Huanggai group,Domestic Reid group,Lancaster group and M group was different.【Conclusion】At the molecular level,43 maize backbone inbred lines were divided into 7 heterosis groups,named Lüda red bone population,Huanggai population,P population,Foreign Reid line,Lancaster population,Domestic Reid line and M group. The backbone inbred lines resistant to stem rot were mainly derived from Lüda red bone group,Foreign Reid group and P group. Maize backbone inbred lines should be used by combined with disease resistance analyzing.

Key words: Maize, Backbone inbred lines, SSR molecular markers, Cluster analysis, Stem rot