The incorporation of the Ren1 gene into a breeding program
to provide resistance to PM makes possible the long-term
support of Run1 gene and decreases the danger of breakdown
of resistance in the event that a new pathogen race appears.
Combining and preserving in the backcross progenies the two
independently inherited resistance genes does not present a difficulty
compared to a polygenic system because selection of the
dominant resistance genes can be achieved using molecular markers.