Use of Host Resistance for Management Wheat Rusts

Wheat is a crop of global importance. The three rust diseases: leaf rust (Puccinia triticina), stem rust (P. graminis tritici), and stripe rust (P. striiformis tritici) are among the most serious constraints to realizing the potential wheat yields. Use of host resistance being efficacious, cost-saving, and environmentally safe, has been the preferred method of wheat rusts’ management. This chapter highlights some of the important insights gained into structural and functional aspects of the genetic basis of rust resistance in wheat, and the successful use of host resistance for wheat rusts’ management. Some of the important sources of rust resistance identified in wheat during recent years are described here. The value of pleiotropic adult plant resistance (APR) genes is being realized worldwide since they impart resistance to multiple wheat pathogens. The potential and limitations of using these genes are discussed. Although the losses caused by wheat rusts have been considerably reduced, recent disease outbreaks in new areas and reports of new virulences probably attributable to climate change and globalization, are posing new challenges to rust resistance breeding. Future thrusts toward realizing effective and long-lasting rust resistance in wheat like characterization and cloning, respectively, of unidentified and promising genes for rust resistance, and identification of gene-specific markers toward gene pyramiding and development of multiple resistance gene cassettes, field pathogenomic analysis to assist in the judicious use of resistance genes and planning of anticipatory breeding approaches, building up global 270cooperation for checkmating the rust pathogens, and harmonizing toward a universal system of nomenclature of wheat rust pathotypes are discussed.