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Resistance

Reciprocal Translocation Testcross Analysis of Genes for Anthracnose Stalk Rot Resistance in a Corn Inbred Line. M. L. Carson, Graduate research assistant, Department of Plant Pathology, University of Illinois, Urbana 61801; A. L. Hooker, professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Phytopathology 72:175-177. Accepted for publication 17 March 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-175.

Nineteen reciprocal translocation testcross populations of corn of the form: (translocation stock × A556) × C123, were evaluated in the field for reaction to anthracnose stalk rot (ASR), which is caused by Colletotrichum graminicola. The translocation stocks involved 15 of the 20 chromosome arms. Partial sterility in translocation heterozygotes was found to reduce ASR severity when compared with fully fertile segregates (homozygous for “normal” chromosomes) in testcross populations. The long arms of chromosomes 1, 4, and 8 and both arms of chromosome 6 were found to carry genes for ASR resistance in A556. The relatively small number of genes or blocks of genes involved indicates that progress in selecting for ASR resistance should be rapid and effective.