Molecular markers for the identification of resistance genes and marker-assisted selection in breeding wheat for leaf rust resistance

The resistance genes Lr9, Lr24, Lr25, Lr29, Lr35 and Lr37, which were not previously utilised in Hungary, have been incorporated into four Martonvasar winter wheat cultivars using marker-assisted selection with PCR-based markers. In the course of a backcross programme, the genes were transferred into Martonvasar wheat varieties and various BC generations were produced. Work aimed at pyramiding resistance genes is currently underway in Martonvasar, and plants containing the gene combinations Lr9 + Lr24, Lr9 + Lr25 and Lr9 + Lr29 are now available. From the BC2F4 generation of the 'Mv Emma'*3/'R. L. 6010' combination ('R.L. 6010' is the donor of the Lr9 gene) 287 lines were tested for leaf rust resistance in an artificially inoculated nursery. A co-dominant primer combination was designed to identify both resistant and susceptible offsprings. The results of resistance tests and molecular marker detection agreed in most cases. Designated leaf rust resistance genes were identified with molecular markers in wheat varieties and breeding lines. The Lr26 and Lr34 resistance genes occur frequently in the Martonvasar gene pool, and the presence of the Lr37 gene has also been detected in a number of Hungarian genotypes.