Recovery of Verticillium dahliae from commercially available potato seed lots planted in Turkey and characterization of isolates by vegetative compatibility and aggressiveness Mehmet Erhan Göre & Belgin Coşge Şenkal & Selma Kuru Berk & Hüseyin Onaran & Nedim Altin & Elif Ay & Selma Tuna & Nusret Zencirci Received: 21 August 2014 /Accepted: 5 October 2014 # Springer Science+Business Media Dordrecht 2014 Abstract A total of 105 seed samples collected from commercially available potato seed lots in Turkey were assayed for Verticillium dahliae. V. dahliae was success- fully isolated from 29 of the 105 seed lots tested. The frequency of infected lots was nearly 28%. Vegetative compatibility of the isolates was assessed through com- plementation tests using nitrate non-utilizing mutants. Of the 110 isolates obtained, 63 were assigned to VCG4A, 24 to VCG4B, 19 to VCG2A and one to VCG2B, while the three remaining isolates could not be assigned to any of the identified VCGs. All 36 of the isolates tested in the greenhouse on potato cv. ‘Russet Burbank’ were pathogenic to potato. As a group, AUDPC values were significantly higher (P <0.05) for VCG4A than for VCG4B and VCG2 isolates. These data suggest that (i) commercial potato seed lots are commonly infected with V. dahliae, and that this is a primary method by which the pathogen can be intro- duced into production fields; (ii) potato isolates of V. dahliae belong to VCG4A, 4B and 2A and these isolates are widely distributed via seed lots; and (iii) VCG4A and VCG4B are distinct pathotypes of V. dahliae that vary in their aggressiveness to potato. The present study is the first report of natural infections of potato by VCG4A and VCG2A in Turkey. Keywords Nit mutants . Seed health . Solanum tuberosum . Verticillium wilt Introduction Damage caused by Verticillium wilt (Verticillium dahliae Kleb.) and its worldwide distribution, makes it one of the main diseases of potato (Dung et al. 2012; Rowe & Powelson 2002). Symptoms of Verticillium wilt of potato include unilateral wilting, chlorosis, and necrosis, which progress acropetally (Dung & Johnson 2012; Johnson & Dung 2010). Yield reductions of be- tween 15% and 50% have been reported but the effects of Verticillium wilt on yield are also influenced by cultural and environmental factors (Cappaert et al. 1992; Johnson et al. 1986; Powelson & Rowe 1993). Since the first decade of the 2000’ s, Verticillium wilt has Phytoparasitica DOI 10.1007/s12600-014-0436-z M. E. Göre (*) Abant Izzet Baysal University, Faculty of Agriculture and Natural Sciences, Department of Plant Protection, Bolu, Turkey e-mail: egore@ibu.edu.tr B. C. Şenkal Bozok University, Faculty of Agriculture and Natural Sciences, Department of Field Crops, Yozgat, Turkey S. K. Berk : S. Tuna Abant Izzet Baysal University, Vocational Higher School, Mudurnu, Bolu, Turkey H. Onaran Potato Research Station, Niğde, Turkey N. Altin Agricon Pesticide Experiment and Consultancy, İzmir, Turkey E. Ay : N. Zencirci Abant Izzet Baysal University, Faculty of Arts and Science, Department of Biology, Bolu, Turkey