Effects of the Ht, Ht2, and/or Ht3 Genes in Three Maize Inbreds on Quantitative Resistance to Exserohilum turcicum Race 2. S. Leath, Former Graduate Assistant, Department of Plant Pathology, University of Illinois, Urbana 61801. W. L. Pedersen, Assistant Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Plant Dis. 70:529-531. Accepted for publication 13 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-529.

Three nonreciprocal diallel sets, each composed of the recurrent parent (A619, B37, or Pa91) and three nearly isogenic lines, each carrying the Ht, Ht2, or Ht3 gene, were evaluated for quantitative resistance to Exserohilim turcicum race 2 in 1983 and 1984. Parents and crosses from the A619 diallel were not significantly (P = 0.05) different from A619 for lesion number or lesion length; however, the parent and crosses carrying the Ht2 gene had significantly lower area under disease progress curve (AUDPC) values than A619. The parent and crosses from the B37 diallel carrying the Ht3 gene had significantly fewer lesions, shorter lesions, and lower AUDPC values than B37. Parents and crosses from the Pa91 diallel did not have significantly smaller lesions or lower AUDPC values than Pa91.