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Resistance

Rate-Limiting Resistance to Pyrenophora Leaf Blotch in Spring Oats. J. A. Frank, Adjunct associate professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802; B. J. Christ, Assistant professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 78:957-960. Accepted for publication 12 February 1988. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1988. DOI: 10.1094/Phyto-78-957.

Several breeding lines of spring oats from the U.S. Department of Agriculture breeding program in Pennsylvania were identified as having a degree of resistance to Pyrenophora leaf blotch in 1979 and 1980 field trials. These lines were evaluated for components of rate-limiting resistance in greenhouse and field tests from 1981 to 1984. In comparison to susceptible cultivars, the relative infection efficiencies were similar. Resistant lines had smaller lesions, longer latent periods, and lower sporulation capacities. Rankings of resistance exhibited in the greenhouse tests were comparable to the disease severity rankings obtained in field trials. The field trials appeared to provide more precision in separating degrees of resistance among breeding lines.