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Resistance

Inheritance of Slow Rusting and the Relationship of Sr Genes to Slow Rusting in the Wheat Line FKN. J. E. Ayers, Visiting associate professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108, Present address: Department of Plant Pathology, The Pennsylvania State University, University Park 16802; J. W. Southern(2), A. P. Roelfs(3), and Roy D. Wilcoxson(4). (2)Graduate assistant, Department of Plant Pathology, University of Minnesota, St. Paul 55108, Present address: Diamond-Shamrock Corporation, Cleveland, OH 44114, (3)Research plant pathologist, Cereal Rust Laboratory, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, University of Minnesota, St. Paul 55108; (4)Professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 71:835-838. Accepted for publication 24 December 1980. 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, 1981. DOI: 10.1094/Phyto-71-835.

Inheritance of resistance (slow rusting) to stem rust (Puccinia graminis f. sp. tritici) was studied in two crosses involving the slow-rusting spring wheat (Triticum aestivum) line FKN and two fast-rusting lines. W3498 and 3-106. The area under the disease progress curve (AUDPC) was used to measure the rate of rusting. Progenies in the F₆ generation of the crosses with FKN were distributed symetrically about the mean. Heritability estimates were 66 and 52% for FKN/W3498 and FKN/3-106 crosses, respectively. The heritability estimate for the cross between the fast-rusting parents was 20%. No relationship was found between the number of Sr genes in individual F₆ progenies and the AUDPC. Although a significantly smaller AUDPC was associated with some Sr genes and combinations of Sr genes, other single Sr genes or combinations of them were associated with higher AUDPCs.