Genetic diversity and phylogenetic analyses of Turkish sweet corn (Zea mays var. saccharata) varieties using ISSR markers and chloroplast trnL-F IGS region

Genetic diversity levels are critical for characterizing and utilizing germplasm collections and for making improvements related to elite germplasms. The current study investigated the genetic diversity level and phylogenetic relationships in ten Turkish sweet corn varieties (Zea mays var. saccharata) using 15 ISSR markers and trnL-F intergenic spacer regions, respectively. A total of 75 loci were identified, of which 57 (76%) were polymorphic. The highest polymorphism ratio (100%) was found using UBC811, UBC817, and UBC823 ISSR markers, while the lowest ratio (45.4%) was identified using UBC829. According to trnL-F intergenic spacer region analyses, nucleotide diversity was found as π: 0.030 for Nei and θ: 0.036 for Watterson, respectively. In trnL-F intergenic spacer regions, several polymorphic (variable) sites were identified 28 of which 57% (16/28) were parsimony informative sites and 399 sites were invariable (monomorphic). The phylogenetic analysis revealed that two major groups were observed named groups A and B and ten sweet corn genotypes clustered along with known maize genotypes in subgroup B2 with 98% bootstrap value. Consequently, the ISSR data obtained in this study revealed that Turkish sweet corn genotypes exhibit extensive genetic diversity, and the trnL-F intergenic spacer region was successfully utilized to differentiate between maize genotypes from various origins and whole plant taxa.