stem rust resistance

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.

Landrace PI 374670 showed resistance to several races of the Ug99 group of Puccinia graminis f. sp tritici in a field stem rust screening nursery in Njoro, Kenya. In these tests PI 374670 showed adult infection responses between resistant (R) and moderately resistant (MR) with a low disease severity (1). In seedling tests showed infection types ranging from ‘;’ to ‘;13’ to races TTKSK, MCCFC and TPMKC.

The SrTA10187 gene originated from Aegilops tauschii accession TA10187, which was collected in Turkmenistan. It is resistant to races TTKSK, TTKST (both Ug99-related) TTTTF, TPMKC RKQQC and QTHJC (the last two are endemic to North America).

SrTA10187 was transferred to KS05HW14, a high yielding hard white winter wheat line resistant to soilborne wheat mosaic virus, wheat streak mosaic virus, and moderately resistant to stripe rust, but susceptible to stem rust races QTHJC, RKQQC, TPMKC, and TTKSK (1).

The SrTA10171 gene was discovered in Aegilops tauschii accession TA10171 from Turkmenistan. This gene is resistant to Ug-99 related races TTKSK and TTKST. It is also confers resistance to RKQQC, QTHJC (both endemic to North America) TTTTF and TPMKC races. SrTA10171 confers a seedling stage resistance thorough a hypersensitive reaction.

The hard red spring wheat line ND643 was used in crosses with CIMMYT germplasm to introgress the high protein content gene gpc-B1. Several lines derived from these crosses showed moderate seedling and adult plant resistance to race TTKSK (Ug99) of Puccinia graminis f. sp. tritici. The gene responsible for this resistance was designated SrND643 (1).

Contributed by Colin Hiebert and Tom Fetch

Original version contributed by Colin W. Hiebert

Bansal et al (1) found a QTL, designated Qsr.sun-5BL, in an Arina/Forno recombinant inbred lines (RIL) population that was responsible for a 12-15 % reduction in stem rust severity. The donor of this QTL was the Arina parent, a Swiss winter wheat cultivar. This QTL was mapped on the distal region of the long arm of chromosome 5B. On a 1-9 scale of rust response (one, resistant; nine, susceptible) cultivar Arina produced a score of six, equivalent to a moderately susceptible response.

Stem rust resistance gene Sr52 was transferred into wheat from the wild diploid relative Dasypyrum villosum. A set of whole arm Robertsonian translocations involving chromosomes 6A of wheat and 6V.3 of D. villosum was produced through centric breakage-fusion (1). D.

Sr50 is a stem rust resistance gene translocated into wheat from rye cultivar Imperial. It is effective against Ug99 races of Puccinia graminis f. sp. tritici and was introgressed into wheat chromosome 1D by translocation from the short arm of rye chromosome rye 1R (1). Two other stem rust resistance genes were also transferred from rye chromosome 1R, Sr31 and SrRAmigo. Using genetic and molecular analysis, Mago et al. (1) showed that Sr50 is a different gene.