Molecular characterization of creole inbred lines from Magdalena, Colombia using Inter Simple Sequence Repeats (ISSRs)

The success of hybrid breeding programs depends heavily on the genetic variability present in the breeding material. Molecular characterization is a key approach for conserving native germplasm and optimizing its use in crop improvement. At the University of Magdalena (Colombia), a collection of maize (Zea mays L.) inbred lines remains genetically uncharacterized. This study assessed the genetic diversity of 15 maize genotypes-14 inbred lines and one commercial hybrid-using seven Inter-Simple Sequence Repeat (ISSR) markers distributed throughout the genome. A total of 2.160 bands were amplified, with fragment sizes ranging from 200 to 1.500 base pairs. The percentage of polymorphic loci varied between 45% and 76.19%, and the expected heterozygosity (He) ranged from 0.17 to 0.39, indicating limited allelic diversity among lines. A fixation index (Fst) of 0.26 revealed moderate genetic differentiation, likely due to restricted gene flow and genetic drift from repeated selfing. Analysis of Molecular Variance (AMOVA) showed that 86% of the total genetic variation occurred within lines rather than between them. Cluster analysis using the UPGMA method grouped genotypes into two main clusters with several sub-clusters. The highest genetic similarity (Nei and Li coefficient = 0.63) was observed between two lines, indicating minimal divergence. Genotype distribution was not associated with geographic origin. These findings provide a foundation for selecting genetically divergent parental lines to enhance heterosis in maize hybrid breeding programs and highlight the value of molecular tools in characterizing and utilizing underexplored germplasm collections.