Search

RL6137, a 'Thatcher' backcross line of wheat (Triticum aestivum L.) has resistance to Puccinia triticina (causal agent of wheat leaf rust) derived from T. monococcum. To determine the chromosome location of this resistance, RL6137 was crossed with Thatcher and F2 individual seedlings were tested for segregation of leaf rust resistance and segregation of polymorphic simple sequence repeat (SSR) markers. Leaf rust resistance genotypes of F2 individuals were confirmed with segregation of F3 families. The F2 seedlings and F3 families segregated for a single leaf rust resistance gene. The SSR markers barc 57 and barc 321 located on chromosome 3AS were tightly linked with the leaf rust resistance gene. The leaf rust resistance gene in RL6137 was designated as Lr63. This gene conditions low to intermediate infection types to most P. triticina isolates and can be used in wheat improvement programs to enhance leaf rust resistance. doi: 10.2135/cropsci2010.01.0005

Leaf rust, caused by the fungus Puccinia triticina Eriks., is a major disease nearly wherever wheat (Triticum spp.) is grown in the USA. Soft red winter wheat (T. aestivum L.) [...]

'Ulen' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-984, PI 639921) cultivar developed and released by the Minnesota Agricultural Experiment Station in cooperation with USDA-ARS in [...]

'Oklee' is a hard red spring wheat (Triticum aestivum L.) (Reg. no. CV-963, PI 634553) developed and released by the Minnesota Agricultural Experiment Station in cooperation with USDA-ARS in January [...]

Leaf rust, caused by Puccinia triticina Eriks., is the most common disease of wheat (Triticum aestivum L.) in the United States and worldwide. The objective of this study was to characterize seedling and adult plant leaf rust resistance in hard red spring wheat cultivars grown in Minnesota, North Dakota, and South Dakota, and postulate the identity of the seedling leaf rust resistance genes in the cultivars. Twenty-six cultivars, near-isogenic lines of Thatcher wheat that differ for single leaf rust resistance genes, and three wheat cultivars with known leaf rust resistance genes, were tested with 11 different isolates of leaf rust collected from the United States and Canada. The leaf rust infection types produced on seedling plants of the cultivars in greenhouse tests were compared with the infection types produced by the same isolates on the Thatcher near-isogenic lines to postulate which seedling leaf rust resistance genes were present. Seedling leaf rust resistance genes Lr1, Lr2a, Lr10, Lr16, Lr21, and Lr24 were postulated to be present in spring wheat cultivars. Seedling genes Lr3, Lr14a, and Lr23 likely were present in some cultivars but could not be clearly identified in this study. Most of the cultivars had some level of adult plant leaf rust resistance, most likely due to Lr34. Cultivars that had seedling resistance genes Lr1, Lr2a, Lr10, or Lr16 had poor to intermediate levels of leaf rust resistance in field plots. Cultivars with combinations of seedling resistance genes Lr16 and Lr24 with additional adult plant resistance were highly resistant to leaf rust. [ABSTRACT FROM AUTHOR]

Collections of Puccinia triticina were obtained from rust-infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, Southeast, California, and the Pacific Northwest, in order to determine the virulence of the wheat leaf rust fungus in 2002. Single uredinial isolates (785 in total) were derived from the wheat leaf rust collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, Lr30, LrB, Lr10, Lr14a, and Lr18. In the United States in 2002, 52 virulence phenotypes of P. triticina were found. Virulence phenotype MBDS, which is virulent to resistance gene Lr17, was the most common phenotype in the United States. MBDS was found in the Southeast, Great Plains, and the Ohio Valley regions, and also in California. Phenotype MCDS, virulent to Lr17 and Lr26, was the second most common phenotype and occurred in the same regions as MBDS. Virulence phenotype THBJ, which is virulent to Lr16 and Lr26, was the third most common phenotype, and was found in the southern and northern central Great Plains region. Phenotype TLGJ, with virulence to Lr2a, Lr9, and Lr11, was the fourth most common phenotype and was found primarily in the Southeast and Ohio Valley regions. The Southeast and Ohio Valley regions differed from the Great Plains regions for predominant virulence phenotypes, which indicate that populations of P. triticina in those areas are not closely connected. The northern and southern areas of the Great Plains were similar for frequencies of predominant phenotypes, indicating a strong south to north migration of urediniospores. [ABSTRACT FROM AUTHOR]

Investigates the virulence of populations of Puccinia triticina in the U.S. in 2001. Analysis of single uredinial isolates from the wheat leaf rust collections; Virulence phenotypes of P. triticina; Virulence to the adult plant resistance genes Lr35and Lr37.