Anatomical variability and population structure of Cucumis melo L. accessions collected from Iran

Melon (Cucumis melo) is one of the most important cultivated cucurbits. In this project, the genetic variability among 14 accessions of melon collected by the authors has been studied using 23 anatomical characteristics across 2 consecutive years as well as 146 random amplified polymorphic DNA (RAPD) markers. Combined analysis of variance revealed significant effects on genotype and year ? genotype effects. Among examined anatomical characters, the highest CV% values across two years belonged to fruit store at room temperature (88.96%, 103.6%) and total fruit weight (42.2%, 40.00%), while the lowest CV% values were observed in flower petal width (0.31%, 0.21%), flower petal length (0.28%, 0.49%), and peduncle length (0.40%, 0.19%). Classification of melon accessions based on anatomical characteristics using the Ward method produced three groups. The highest Jaccard?s similarity coefficient (0.76) was observed between accessions ?Atashi koluche? and ?Atashi miyaneh? and the lowest value (0.49) was found between accessions ?Bakermellon? and ?Mashhadi? with the mean value of 0.59. In this study, OPA06 and OPB13 primers possessed greater efficiency in the genetic evaluation of the studied germplasm. Analysis of population structure, which imply on the existence of admixture in the studied melon germplasm, revealing three subpopulations. Accession ?Sabzevari? identified as mixed subgroups. From the breeder?s view, the introduced heterotic groups can be utilized in parental selection for the construction of mapping population and the identified population structure can prevent any false positive output in marker-trait association studies of melon.