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Studies on Wheat Stem Rust Resistance Controlled at the Sr6 Locus. I. The Role of Phenolic Compounds. Paul M. Seevers, Department of Biochemistry and Nutrition, University of Nebraska, Lincoln 68503; J. M. Daly, Department of Biochemistry and Nutrition, University of Nebraska, Lincoln 68503. Phytopathology 60:1322-1328. Accepted for publication 16 March 1970. DOI: 10.1094/Phyto-60-1322.

Leaves of healthy or inoculated paired near-isogenic lines of wheat carrying either the Sr6 allele for resistance or the sr6 allele imparting susceptibility to race 56 of Puccinia graminis tritici were analyzed for total, combined, and bound phenols. A number of extraction procedures and several chemical methods were employed. Contrary to previous reports, no significant differences in total phenolic compounds were found among healthy or inoculated, resistant and susceptible, plants at any stage of disease development. Analysis of the concn of individual aromatic compounds by paper, thin-layer, or gas chromatography also failed to reveal any correlations with resistance or susceptibility. It is concluded that, if aromatic compounds are involved in the expression of resistance controlled at this gene locus, such involvement cannot be demonstrated by techniques employed previously in studies of other host-parasite combinations.