Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2007
Publication Date: 5/1/2008
Citation: Barrett, B., Faris, J.D., Fellers, J.P. 2008. Molecular Mapping of the leaf rust resistance gene Lr17a in Wheat. Crop Science.48:1124-1128. Interpretive Summary: Leaf rust is one of the most significant diseases that affects wheat. Application of chemical fungicides are often not economical and thus, disease must be combated using genetics. Effective resistance genes are found in germplasm sources and are bred into new varieties. However, it is sometimes difficult and labor intensive to determine whether a wheat cultivar has a particular gene or not. Thus, molecular tools are derived to help follow certain genes in populations. In this work, molecular markers have been found that can be used to identify the resistance gene Lr17a, in wheat. This gene is in numerous cultivars. Now that markers have been found, breeders can accurately determine if the gene is present in their lines, without the need for screening with the pathogen.
Technical Abstract: Wheat leaf rust, caused by Puccinia triticina, is a constant problem for North American wheat producers. Each year, millions of acres of wheat are infected by this economically important fungus. The infected leaves senesce prematurely, affecting the ability of the wheat plant to complete kernel fill, in turn reducing yield. Lr17a, a leaf rust resistance genes in wheat, is present in many wheat varieties available today. The objective of this research is to identify molecular markers linked to Lr17a. Microsatellite markers were used on a mapping population made from a cross of Chinese Spring and Thatcher-Lr17a. Capillary fragment analysis was performed and eight markers were linked to Lr17a. Xgwm614 distally flanked at 0.7 cM while Xgwm407 was proximally located at 2.5 cM. Alleles for the locus are variable, but can be used for selection.