Genetic diversity between and within Iranian melon accessions, and their relationships with melon germplasm of diverse origins, using microsatellite markers

A set of 18 Simple Sequence Repeat (SSR) primer pairs was employed to assess the genetic diversity in a collection of 52 melon genotypes that consisted of 24 melon accessions representing different horticultural groups of Iranian cultivated melons, along with 28 reference accessions from diverse foreign geographical origins. All the studied SSR loci were polymorphic, confirming their potential for genetic analysis in melons. A total number of 141 alleles were detected among all the genotypes, out of which 79 alleles with an average of 4.38 alleles per locus were observed for the Iranian accessions. The low variability within Iranian melon accessions was reflected by the low values of the observed heterozygosity (with an average of 0.12), indicating either a lack of intercrossing between accessions or a high rate of inbreeding. Consecutive selections by farmers for keeping accession traits might be considered as an explanation for the relatively high observed homozygosity. Values of observed homozygosity for ‘Suski-e sabz’ and ‘Khatouni’, as the most cultivated melons in Iran, amounted to 0.98 and 0.99, respectively. The highest level of polymorphism was detected among the Group Dudaim populations (with 100 percent of polymorphic loci).