Assessment of genetic diversity in maize (Zea mays L.) landraces using inter simple sequence repeat (ISSR) markers
Valdemar P. Carvalho; Paulo M. Ruas; Claudete F. Ruas; Josué M. Ferreira and Rosângela M. P. Moreira
Inter Simple Sequence Repeat (ISSR) markers were used to assess the genetic relationships among 79 landraces and two improved varieties of maize cultivated in Brazil. Nine primers comprising dinucleotides (GA)9, (AT)9, trinucleotides (GTG)6, (TAG)6, and the tetranucleotides (GATA)4, (GACA)4, (CCTA)4, and (GGTA)4 were used for PCR amplifications. From a total of 153 DNA fragments produced, 116 (75.8%) were found to be polymorphics. The dinucleotide motifs (GA)9T and (GA)9C combined with other di-, tri- and tetra-nucleotides produced a greater number of DNA fragments, which suggests a high frequency of the poly GA microsatellite motifs in the maize genome. The UPGMA clustering algorithm associated the varieties into three major groups that were correlated to the endosperm colors and fourteen sub clusters that were mostly related to the flowering time. The results revealed that ISSR markers could be efficiently used to quickly access the genetic variation available in the maize germplasm. The information on genetic similarity among varieties will be useful for selecting the accessions to establish a germplasm bank of maize landraces and to develop breeding programs.