leaf rust resistance

The Swiss winter bread wheat cultivar "Forno" has been showing near immune levels of leaf rust resistance since its release in 1986. At least six different loci contribute to this phenotype (1). The largest fraction of the phenotipic variation (33-43%) is explained by Lr34. Regretfully, this gene is associated with leaf tip necrosis, an undesirable trait in Western Europe breeding programs. The same authors determined that the second largest source of variation (28–32%) was due to a loci on chromosome arm 1BS, named QLr.sfr-1BS (1).

Contributed by Sybil Herrera-Foessel, Ravi Singh and Evans Lagudah

Triticum speltoides Taush (2n = 14, S genome) is an attractive source of high levels of resistance to leaf, stem and stripe rust of wheat (1). Leaf rust resistance genes Lr28, Lr35, Lr36,and Lr47 were derived from this species (3). Crosses between T. speltoides and hexaploid wheat (T. aestivum L.

Contributed by Gina Brown-Guedira and Suhkwinder Singh

Host plant resistance is an economical and environmentally sound method of control of leaf rust, caused by the fungus Puccinia triticina Eriks, which is one of the most serious diseases of wheat (Triticum aestivum L.) worldwide. Wild relatives of wheat, including the tetraploid Triticum timopheevii ssp. armeniacum (hereafter referred to as T. armeniacum), represent an important source of genes for resistance to leaf rust (3).

The leaf rust resistance gene Lr47 confers resistance to a wide spectrum of leaf rust strains. This gene was transferred from chromosome 7S of Triticum speltoides to chromosome 7A of Triticum aestivum. Initially, the RFLP locus Xabc465 was used to follow the transfer of the segment containing Lr47 (1), but later, this marker was converted into a dominant PCR marker.

We acknowledge valuable contributions made by Gina Brown-Guedira during the preparation of this page.

Contributed by Marcelo A. Soria, Wenjun Zhang and Jorge Dubcovsky. KASP marker contributed by Gina Brown-Guedira. We also acknowledge valuable contributions by Harbans Bariana, Manilal William, Beat Keller, Evans Lagudah and Bob McIntosh.

Contributed by Gina Brown-Guedira and Suhkwinder Singh

Contributed by C. Hiebert

Lr32 is a gene transferred from Aegilops tauschii to chromosome arm 3DS of hexaploid wheat that confers seedling stage resistance to leaf rust (1,2). The original accession of A. tauschii in which Lr32 was found was RL5497-1 (2n = 14 = DD), which was crossed with Tetra Canthatch (2n = 28 = AABB) to produce the synthetic hexaploid line RL5713. Lr32 was transferred from RL5713 to RL6086 (Thatcher*7//RL5713/MarquisK) and to BW196 (Katepwa*6//RL5713/2*MarquisK).

Contributed by J. Douglas Procunier. Agriculture & AgriFood Canada