Characterization of Iranian melon landraces of Cucumis melo L. Groups Flexuosus and Dudaim by analysis of morphological characters and random amplified polymorphic DNA

Diversity among Iranian melon landraces of Groups Flexuosus and Dudaim was studied by analyzing morphological and physiological traits and by random amplified polymorphic DNA (RAPD). Thirty-one morphological and physiological traits showed significant variation among accessions. Some Flexuosus accessions had typical morphological characters of elongated fruit shape, light skin color, ribs on fruit skin and non-sweet flesh. Characters distinct from in typical accessions, such as short fruits, dark green skin color, five carpels, sweet flesh, were especially in ribless accessions. Cluster analysis of morphological and physiological characters divided Iranian melon into seven groups. Dudaim (cluster VII) was clearly separated from Flexuosus, in which typical (cluster I) accessions and atypical accessions (clusters III-VI) were grouped separately. The diversity index shown by RAPD was 0.201 in 25 Flexuosus accessions and was rich in genetic diversity. Cluster analysis using RAPD divided Flexuosus accessions into eight subclusters, and clarified genetic similarity between Iranian melon accessions and reference accessions of large-seed type (Groups Inodorus and Cantalupensis). These results may suggest that large-seed Flexuosus, Inodorus and Cantalupensis are not differentiated genetically, probably due to spontaneous inter-group hybridization.