African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6844

Full Length Research Paper

Genetic diversity among crown and root rot isolates of Rhizoctonia solani isolated from cucurbits using PCR-based techniques

Seyed Mahyar Mirmajlessi1*, Naser Safaie1, Hossein Ahari Mostafavi2, Seyed Mojtaba Mansouripour1 and Seyed Bagher Mahmoudy3
  1Department of Plant Pathology, College of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran. 2Nuclear Science and Technology Research Institute, Agricultural, Medical and Industrial Research School, Karaj, Iran. 3Sugar Beet Seed Institute (SBSI), Karaj, Iran.
Email: [email protected]

  •  Accepted: 12 December 2011
  •  Published: 31 January 2012



Twenty three (n=23) isolates of Rhizoctonia solani were obtained from root, crown and rhizosphere of cucumber, pumpkin, watermelon and melon plants. Investigation of the anastomosis groups (AGs) showed that all of the isolates belonged to AG4. Twenty three of R. solani AG4 were measured for disease severity according to their geographical origins and host plants. The pathogenicity test revealed that the disease severity varied from 8.3 to 91.6%, when all isolates were inoculated on their corresponding hosts. The disease severity indicated that R. solani isolates were classified into five groups. Genetic diversity was performed among isolates of R. solani AG4 by combination of random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) techniques. Amplicon size of six RAPD primers out of fifteen and four ISSR primers out of ten, ranged from 0.5 to 3 Kb in isolates. All isolates were divided into seven groups at >30% similarity level. The results exhibited a high genetic variability in the R. solani AG4 population, without any correlation between genetic diversity, the host plants and geographical regions.


Key words: Cucurbits, genetic diversity, random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), pathogenicity, Rhizoctonia solani.