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Thirty‐five genes for low reaction to Puccinia recondita Rob. ex Desm. (Lr genes) in wheat, Triticum aestivum L., have been studied and named in a sequential number series by different authors. This paper summarizes information about these named Lr genes. Information on origin, chromosome location, characteristic low infection types, relative environmental sensitivity, synonymy, reference host lines, and reference cultures is summarized.Five Lr genes, Lrl2, Lrl3, Lr22a, Lr22b, and Lr26 can be detected only by inoculating adult plants with an avirulent culture; the others can be detected by inoculating seedling plants with an appropriate cullture. Characteristic low infection types conditioned by Lr genes and their corresponding Lr genes range from 01C, where only very small flecks occur, to 56X to 78X where extensive sporulation occurs. Post‐infection Temperature influences the expression of all Lr genes; but some, Lr11, Lr12. Lr13, Lrl4a, and Lrl8 are especially sensitive to high temperatures. The name Lr genes have been shown to occur on 13 different chromosomes, in all 3 common wheat genomes. Lr genes and their corresponding genes for pathogenicity are the basis for storing and retrieving information about specificity in the P. recondita:Triticum system.

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