Molecular mapping of the leaf rust resistance gene Rph7 in barley

Leaf rust of barley, caused by Puccinia hordei Otth, is an important foliar disease in most temperate regions of the world. Sixteen major leaf rust resistance (Rph) genes have been described from barley, but only a few have been mapped. The leaf rust resistance gene Rph7 was ®rst described from the cultivar `Cebada Capa' and has proven e€ective in Europe. Previously mapped restriction fragment length polymorphism (RFLP) markers have been used to determine the precise location of this gene in the barley genome. From the genetic analysis of a `Bowman'/`Cebada Capa' cross, Rph7 was mapped to the end of chromosome 3HS, 1.3 recombination units distal to the RFLP marker cMWG691. A codominant cleaved ampli®ed polymorphic site (CAPS) marker was developed by exploiting allele-speci®c sequence information of the cMWG691 site and adjacent fragments of genomic DNA. Based on the large amount of polymorphism present in this region, the CAPS marker may be useful for the marker-assisted selection of Rph7 in most diverse genetic backgrounds.