Characterization of the Rust Fungus, Puccinia emaculata, and Evaluation of Genetic Variability for Rust Resistance in Switchgrass Populations

Srinivasa Rao Uppalapati, Desalegn D. Serba, Yasuhiro Ishiga, Les J. Szabo, Shipra Mittal, Hem S. Bhandari, Joseph H. Bouton, Kirankumar S. Mysore, Malay C. Saha

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Several fungal pathogens have been identified on ornamental and native stands of switchgrass (Panicum virgatum L.). Diseases of switchgrass, particularly rust, have been largely neglected and are likely to become the major limiting factor to biomass yield and quality, especially when monocultured over a large acreage. Based on teliospore morphology and internal transcribed spacer-based diagnostic primers, the rust pathogen collected from switchgrass research fields in Oklahoma was identified as Puccinia emaculata. Furthermore, to identify genetically diverse source(s) of rust resistance, several switchgrass genotypes from both upland (cv. 'Summer' and 'Cave-in-Rock') and lowland (cv. 'Alamo' and 'Kanlow') ecotypes were evaluated in Ardmore, Oklahoma during 2008 and 2009 and in growth chamber assays. Field and growth chamber evaluations revealed a high degree of genetic variation within and among switchgrass cultivars. In general, Alamo and Kanlow showed moderate resistance to P. emaculata, while Summer was highly susceptible. Distinct ecotypic variations for reactions to rust were also prevalent with the lowlands maintaining a high level of resistance. These results suggest the potential for improvement of rust resistance via the selection of resistant individuals from currently available cultivars. Further, the selection pressure on the pathogen would also be reduced by employing several rust resistant cultivars in production-scale situations.

Original languageEnglish (US)
Pages (from-to)458-468
Number of pages11
JournalBioenergy Research
Issue number2
StatePublished - Jun 2013
Externally publishedYes


  • Genetic variability
  • Host resistance
  • Internal transcribed spacer (ITS)
  • Panicum virgatum
  • Puccinia emaculata
  • Switchgrass rust


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