8th INTERNATIONAL WHEAT CONFERENCE

LeAf RuST ReSISTANCe geNe LR67, A ThIRd AduLT PLANT
SLoW-RuSTINg geNe CoNfeRRINg ReSISTANCe To
muLTIPLe PAThogeNS of WheAT
Colin Hiebert 1 , Wolfgang Spielmeyer 4 Julian Thomas 1 ,
Brent McCallum 1 , Matthew Hayden 3, Gavin Humphreys 1 ,
Ron DePauw 2 , Rohit Mago 4 , Wendelin Schnippenkoetter 4
1 Cereal Research Centre, Agriculture and Agri-Food Canada, 195 Dafoe Rd., Winnipeg,
Manitoba, Canada, R3T 2M9
2 Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, P.O.
Box 1030, Airport Rd., Swift Current, Saskatchewan., Canada, S9H 3X2
3 Victorian Department of Primary Industries, Victorian AgriBioscience Centre, La Trobe
Research and Development Park, Bundoora, VIC 3082, Australia
4 CSIRO Plant Industry, GPO Box 1600, Canberra ACT 2601, Australia.
E-mail Address of presenting author: colin.hiebert@agr.gc.ca
There is increasing interest in genes that confer partial, adult plant resistance (APR) to the
rust pathogens of wheat (Triticum aestivum L.). Until now, two genes leaf rust resistance
(Lr) genes, Lr34 and Lr46, have been identified as conferring APR to leaf rust and stripe
rust. Here we report a third gene, Lr67, which confers resistance to leaf rust and stripe
rust. This resistance gene was found in the wheat line PI250413 and was previously isolated
in RL6077 (= Thatcher*6/PI250413). A genome-wide scan of SSR markers detected
introgressions from chromosomes 4D, 2A, 5D and 6B of PI250413 that were retained in
RL6077 after five backcrosses to Thatcher. Haplotype analysis lines that were homozygous
resistant or susceptible from crosses of Thatcher x RL6077 and RL6058 (Thatcher*6/
PI58548) x RL6077 showed highly significant associations between introgressed markers
on chromosome 4DL and leaf rust and stripe resistance. The SSR markers retained
on the other chromosomes of RL6077 showed no association with leaf rust phenotypes.
Haplotypes and deletion mapping suggest that the SSR marker cfd71 is closely linked to
APR to leaf rust from RL6077. In an additional population derived from RL6077, APR
to stripe rust was also tightly linked with cfd71 on chromosome 4DL. No other Lr genes
are located on chromosome 4D, thus Lr67 is a new gene. In field trials, Lr34 performed
better than Lr67; however Lr67 provided effective resistance in each year and location. In
a strategy where APR is utilized to develop durably resistant cultivars, Lr67 represents a
valuable genetic resource for wheat breeding.
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