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Etiology

Tilletia indica: A Heterothallic Wheat Bunt Fungus with Multiple Alleles Controlling Incompatibility. Rubén Durán, Professor, Department of Plant Pathology, Washington State University, Pullman, WA 99163; Robert Cromarty, former Research Technologist, Department of Plant Pathology, Washington State University, Pullman, WA 99163, Present address junior author: 4225 Sturdivant Drive, Klamath Falls, OR 97601. Phytopathology 67:812-815. Accepted for publication 27 January 1977. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-812.

To elucidate the relation between incompatibility alleles which govern heterothallism and pathogenicity, paired and nonpaired monosporidial lines of the Karnal bunt fungus (Tilletia indica) were used to inoculate wheat heads in the boot stage or during anthesis. Paired lines which proved pathogenic were postulated to be of different mating types, whereas nonpathogenic pairs were postulated to consist of the same mating type. In all cases, nonpaired lines were nonpathogenic. From results obtained in testing 93 monosporidial lines, it is suggested that heterothallism and pathogenicity are controlled by multiple alleles at one locus; four such alleles were demonstrated in the material studied. Consistent with the bipolar incompatibility system posulated for the fungus, basidia yielded only monosporidial lines of two mating types.