Original Paper

Theoretical and Applied Genetics

, Volume 123, Issue 1, pp 55-68

First online:

Mapping Rph20: a gene conferring adult plant resistance to Puccinia hordei in barley

  • L. T. HickeyAffiliated withThe University of Queensland, School of Agriculture and Food Sciences Email author 
  • , W. LawsonAffiliated withDepartment of Employment, Economic Development and Innovation, Hermitage Research Station
  • , G. J. PlatzAffiliated withDepartment of Employment, Economic Development and Innovation, Hermitage Research Station
  • , M. DietersAffiliated withThe University of Queensland, School of Agriculture and Food Sciences
  • , V. N. AriefAffiliated withThe University of Queensland, School of Agriculture and Food Sciences
  • , S. GermánAffiliated withInstituto Nacional de Investigación Agropecuaria, La Estanzuela
  • , S. FletcherAffiliated withDepartment of Employment, Economic Development and Innovation, Leslie Research Centre Toowoomba
  • , R. F. ParkAffiliated withThe University of Sydney, Plant Breeding Institute-Cobbitty
  • , D. SinghAffiliated withThe University of Sydney, Plant Breeding Institute-Cobbitty
    • , S. PereyraAffiliated withInstituto Nacional de Investigación Agropecuaria, La Estanzuela
    • , J. FranckowiakAffiliated withDepartment of Employment, Economic Development and Innovation, Hermitage Research Station

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Abstract

A doubled haploid (DH) barley (Hordeum vulgare L.) population of 334 lines (ND24260 × Flagship) genotyped with DArT markers was used to map genes for adult plant resistance (APR) to leaf rust (Puccinia hordei Otth) under field conditions in Australia and Uruguay. The Australian barley cultivar Flagship carries an APR gene (qRphFlag) derived from the cultivar Vada. Association analysis and composite interval mapping identified two genes conferring APR in this DH population. qRphFlag was mapped to the short arm of chromosome 5H (5HS), accounting for 64–85% of the phenotypic variation across four field environments and 56% under controlled environmental conditions (CEC). A second quantitative trait locus (QTL) from ND24260 (qRphND) with smaller effect was mapped to chromosome 6HL. In the absence of qRphFlag, qRphND conferred only a low level of resistance. DH lines displaying the highest level of APR carried both genes. Sequence information for the critical DArT marker bPb-0837 (positioned at 21.2 cM on chromosome 5HS) was used to develop bPb-0837-PCR, a simple PCR-based marker for qRphFlag. The 245 bp fragment for bPb-0837-PCR was detected in a range of barley cultivars known to possess APR, which was consistent with previous tests of allelism, demonstrating that the qRphFlag resistant allele is common in leaf rust resistant cultivars derived from Vada and Emir. qRphFlag has been designated Rph20, the first gene conferring APR to P. hordei to be characterised in barley. The PCR marker will likely be effective in marker-assisted selection for Rph20.