A molecular marker of leaf rust resistance gene Lr37 in wheat

Inter-simple sequence repeat (ISSR) analysis was carried out in Thatcher, 20 near-isogenic lines (NILs) containing respectively different genes conferring resistance against wheat leaf rust (Puccinia recondite f.sp. tritici), three materials carrying Lr37 and three materials without Lr37. All of the 100 ISSR primers showed clear amplification products. Two of them amplified the polymorphic DNA bands in the NILs, Thatcher and Lr37/6*Thatcher. The polymorphic bands were named UBC812-1200 and UBC848-700, respectively. The three materials with and without Lr37 were detected in tests using the two primers UBC812 and UBC848. Results also showed that only band UBC812-1200 was amplified in all resistant and absent in all susceptible materials. This suggests that UBC812-1200 marker is linked to the resistance gene Lr37. The genetic linkage of the polymorphic marker with Lr37 was tested using a segregating F2 population (128 plants) derived from a cross between the leaf rust-resistant Lr37/6*Thatcher and the susceptible cultivar Thatcher. The ISSR marker UBC812-1200 showed co-segregation to the Lr37 resistance gene. It could be used in molecular marker-assisted selection in a wheat breeding programme for leaf rust resistance.