Wednesday, November 7, 2007 - 8:15 AM
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Resistance Screening of Festuca arundinacea Germplasm to Rhizoctonia Species Using Digital Image Analysis.

Virginia R. Sykes1, Brandon Horvath1, and Scott Warnke2. (1) Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, 1444 Diamond Springs Rd, Virginia Beach, VA 23455, (2) USDA-ARS, USDA-ARS, 10300 Baltimore Ave., Beltsville, MD 20705

A major disease affecting tall fescue lawns in the transition zone is brown patch, caused by the fungus Rhizoctonia solani. A related pathogen, Rhizoctonia zeae, presents similar symptoms, but is not usually included in the screening process when developing brown patch resistant cultivars. This exclusion, along with the subjectivity of visual evaluation methods used in determining disease severity, may contribute to the high variability in brown patch disease resistance observed among currently available cultivars. The objectives of this study were to: 1) develop digital image analysis methods to accurately evaluate the disease severity of tall fescue leaves and whole plants, and 2) use DIA to screen accessions of tall fescue from the USDA germplasm database to determine their resistance to both R. solani and R. zeae.