(McIntosh, 1988a) (Plate 3-38)


SrTt2 (McIntosh and Gyarfas, 1971).

Chromosome Location

4B (Gyarfas, 1978).

Low Infection Type

0;, ;1, ;3C, depending on pathogen culture (McIntosh and Gyarfas, 1971). Susceptible off-types are relatively common.

Environmental Variability

Low (Roelfs and McVey, 1979).


T. timopheevii.

Pathogenic Variability

Luig (1983) discussed results of an international survey which indicated that virulence for Sr37 occurred in the USA, Canada, Brazil, Pakistan, India, Italy and Israel. Virulence for Sr37 has not been detected recently in the USA (Roelfs et al., 1990, 1991), or in the regions surveyed by Huerta-Espino (1992).

Reference Stocks

v. Line W = W3563 (McIntosh and Gyarfas, 1971).

tv: Various accessions of T. timopheevii of which W1899 and C.I.11802 should be regarded as the standards (McIntosh and Gyarfas, 1971).

Source Stocks

Other sources of T. timopheevii are listed in McIntosh and Gyarfas (1971).


Seedling leaves of (L to R): Line W, Mengavi (Sr36), a Federation cross with SrTt3 and Federation; infected with A. pt. 126-5, 6, 7, 11 [P37], B. pt. 34-2, 4, 5, 7, 11 [P37], C. pt. 34-1, 2, 3, 6, 7, 8, 9 [P37], D. pt. 34-1, 2, 3, 4, 5, 6, 7, [P37] and E. pt. 34-(4), (7), 10 [P37]. Line W is resistant to all cultures but there is variation in infection type. The second and fourth cultures are virulent for Sr36 in Mengavi. The Federation line with SrTt3 is highly resistant to pt. 126-5, 6, 7, 11 (A.) and gives an intermediate response in B., C. and D. Pt. 34-(4), (7), 10 (E.) is virulent on the SrTt3 stock but Federation is resistant probably due to the presence of Sr10. Earlier records indicated that lines with Sr36 give intermediate responses with pt. 34-(4), (7), 10. The high level of resistance to pt. 34-(4), (7), 10 indicated that Mengavi may carry an additional gene for resistance to this atypical pathotype, which is suspected to be a somatic hybrid of P. graminis f. sp. tritici and P. graminis f. sp. secalis.


Use in Agriculture

Sr37 has not been exploited in cultivated durums or common wheat. Although potentially useful for gene combinations from a pathological viewpoint, the T. timopheevii chromosome segment (indeed most of the 4B chromosome) bearing Sr37 has only limited homology with the equivalent chromosome in common wheat (Gyarfas, 1978; Dvorak et al., 1990). Consequently, any common wheat line with Sr37 would have to be derived from a translocation event leading to increased chromosomal homology with wheat chromosome 4B.

McIntosh and Gyarfas (1971) concluded there may be as few as three genes for resistance to stem rust in T. timopheevii, that is, Sr36, Sr37 and possibly a third factor present in the common wheat derivative C.I.13005 (Atkins, 1967). Gyarfas (1978) later presented evidence for a fourth gene which she designated SrTt3 in the common wheat derivative, Line AH (see SrTt3).