Race-Specific Adult-Plant Resistance in Winter Wheat to Stripe Rust and Characterization of Pathogen Virulence Patterns.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of wheat in the Great Plains and southeastern United States.

Characterization of Stripe Rust Resistance in Wheat Lines with Resistance Gene Yr17 and Implications for Evaluating Resistance and Virulence.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, has been the most important foliar wheat disease in south central United States since 2000 when a new strain of the pathogen emerged.

Characterization of Resistance to Stripe Rust in Contemporary Cultivars and Lines of Winter Wheat from the Eastern United States.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, has been an important disease of winter wheat (Triticum aestivum) in the eastern United States since 2000, when a new strain of the pathogen emerged.

Resistance in Winter Wheat Lines to Initial Infection and Spread Within Spikes by Deoxynivalenol and Nivalenol Chemotypes of Fusarium graminearum.

Head blight of wheat in the United States is caused primarily by the deoxynivalenol (DON)-producing chemotype of Fusarium graminearum. However, the discovery of the nivalenol (NIV) chemotype of F. graminearum in Louisiana and Arkansas necessitates having resistance in wheat to both chemotypes.

Nivalenol-type populations of Fusarium graminearum and F. asiaticum are prevalent on wheat in southern Louisiana.

U.S. populations of the Fusarium graminearum clade cause head blight on wheat and barley and usually contaminate grain with the trichothecene mycotoxin deoxynivalenol (DON).

Evidence for increased aggressiveness in a recent widespread strain of Puccinia striiformis f. sp. tritici causing stripe rust of wheat.

Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, has become more severe in eastern United States, Australia, and elsewhere since 2000.

Rapid global spread of two aggressive strains of a wheat rust fungus.

Rust fungi can overcome the effect of host resistance genes rapidly, and spores can disperse long distance by wind. Here we demonstrate a foreign incursion of similar strains of the wheat yellow rust fungus, Puccinia striiformis f. sp.

Genes for Adult-Plant Resistance to Leaf Rust in Soft Red Winter Wheat.

Host plant resistance in wheat (Triticum aestivum) has been the principal means of managing leaf rust caused by Puccinia triticina. The need for durable resistance has changed the focus from the use of seedling resistance to adult-plant resistance. The objectives of this study were to determine the genetic basis for adult-plant resistance and to determine the most effective method to identify adult-plant resistance genes Lr12, 13, and 34 among 116 contemporary soft red winter wheat cultivars and breeding lines.

A Computer Program to Improve the Efficiency and Accuracy of Postulating Race-Specific Resistance Genes.

Gene postulation has been the most widely used technique to determine the presence of particular rust resistance genes in lines of small grains. It applies the principles of gene-for-gene specificity to determine the most probable race-specific resistance genes present in host lines. As the numbers of lines, resistance genes, and races increase, postulation based on visual comparisons of infection types becomes more complex and laborious, and errors may occur.

Seedling Resistance Genes to Leaf Rust in Soft Red Winter Wheat.

Seedling and adult-plant resistance have been used to manage leaf rust, caused by Puccinia triticina, but there is little information on resistance genes in contemporary cultivars and advanced breeding lines of soft red winter wheat (Triticum aestivum). Lack of information on the genetic basis for resistance leads to uncertainty about durability of resistance and makes pyramiding resistance genes more difficult. The objective of this study was to determine the genetic basis for race-specific seedling resistance to leaf rust among the 116 contemporary lines from the 1998-99 Arkansas Wheat Cultivar Performance Test and the Uniform Eastern and Southern Soft Red Winter Wheat Nurseries.

Wheat Stripe Rust Epidemics and Races of Puccinia striiformis f. sp. tritici in the United States in 2000.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is most destructive in the western United States and has become increasingly important in the south-central states.