Molecular characterization of Ditylenchus dipsaci on Onion in Turkey

Ditylenchus dipsaci is a species complex including diploid and polyploid individuals. The onion race of D. dipsaci is a sensu stricto group and has a wide range of host spectrum. Identification of the D. dipsaci onion race is difficult using morphological and morphometrical methods. Species specific primers are mostly used in molecular approaches for identification of D. dipsaci populations. Fifty one morphologically selected Ditylenchus spp. populations from onion production areas in Turkey were subjected to molecular identification using four D. dipsaci species specific primer sets (PF1-PR1, PF2-PR2, DdpS1-rDNA2, DitNF1- rDNA2, H05-H06) targeting 5.8S and 18S rDNA, ITS1 and flanking ITS regions. Thirty nine percent of the nematode samples were positive with four primers tested, while four of the nematode samples gave specific bands with H05-H06 primers. Ditylenchus dipsaci sensu stricto was identified with specific primer sets in Adana, Hatay, Tekirdag, Bursa, Aksaray, Karaman, Eskisehir and Ankara provinces in Mediterranean, Trace, Aegean and Central Regions in Turkey.