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Resistance

Genetics of Rust Resistance of Six Argentinian Flax Introductions. D. E. Zimmer, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, North Dakota State University, Fargo, North Dakota 58102; G. D. Statler, Associate Professor, Department of Plant Pathology, North Dakota State University, Fargo, North Dakota 58102. Phytopathology 66:661-663. Accepted for publication 19 December 1975. DOI: 10.1094/Phyto-66-661.

Six Argentinian introductions of seed flax (Linum usitatissimum) resistant to races of Melampsora lini that collectively attack lines monogenic for known genes for resistance except M⁶ and P⁴, were analyzed genetically for previously unknown rust-resistance genes. The F₂ segregation ratios for resistance to races 1, 22, 73, and 312, between each introduction and Bison, was explained without postulating the existence of any unknown genes. All introductions were postulated to contain the N gene. Cereal introductions C.I. 2834 and C.I. 2837 also possessed a gene that conditioned resistance against races 1, 73, and 312, but was ineffective against race 22. Cereal introductions C.I. 2829, C.I. 2830, C.I. 2834, and C.I. 2835 possessed two additional genes that were differentially effective against two or more of the tester races.