The use of differential isolates of Rhynchosporium secalis to identify resistance to leaf scald in barley

摘要

The presence of seedling resistance to leaf scald in Australian barley varieties and breeding lines has been determined using differential pathotypes of Rhynchosporium secalis. The previously described resistance genes Rrs1, Rrs2 and Rh4/Rh10 have been identified as well as other resistance sources that show different reactions against the isolates. Seedling resistance in the barley variety Skiff, Rh (Skiff), has been found to react in an identical fashion to seedling resistance in the variety Barque suggesting the same gene/allele is present in these varieties. Virulence in R. secalis has been detected against almost all barley resistance sources tested, reinforcing previous experience that single gene resistance to scald is not a safe option. The differential isolates are being used to detect resistance genes in breeding lines as a service to barley breeding programs. They are also being used to detect novel resistances and will prove useful to breeders in building gene pyramids to try and develop varieties with more durable resistance.