(McIntosh, 1988a) (Plate 3-34)
Synonym
SrSQ (Kerber and Dyck, 1979).
Chromosome Location
1DL (Kerber and Dyck, 1979). Because of linkage with Lr21, Rg2 and Gli-D1 (Jones et al., 1990), Sr33 must be located in 1DS. Czarnecki and Lukow (1992) mapped it 9 cM from Gli-D1 whereas Jones et al. (1991) obtained estimates of 5.6 and 7.6 cM for the same interval. Sr33 was proximal to Gli-D1.
Low Infection Type
;1- in diploid stocks, 2 in hexaploid derivatives (Kerber and Dyck, 1979). Huerta-Espino (1992) recorded ITs 1-C to 2.
Environmental Variability
None reported.
Origin
T. tauschii R.L.5288.
Pathogenic Variability
Virulence has not been reported, but lines with Sr33 have not been tested widely. Pathogenicity surveys in the USA (Roelfs et al., 1991), Mexico (Singh, 1991) and Australia as well as the study of Huerta-Espino (1992) failed to detect virulence for Sr33.
Reference Stocks
v: R.L.5405 = C78.15 = Tetra Canthatch/T. tauschii R.L.5288 (Kerber and Dyck, 1979).
dv: T. tauschii R.L.5288 (Kerber and Dyck, 1979).
Source Stocks
Several Australian backcross derivatives produced at The University of Sydney Plant Breeding Institute.
Use in Agriculture
No wheat with Sr33 has been commercialised. Kerber and Dyck (1979) reported that Sr33 was closely linked in repulsion with Lr21. RA McIntosh (unpublished, 1981) tested F3 lines of the Sr33/Lr21 cross produced by ER Kerber, and demonstrated the proximity of Sr33 to both Lr21 and a stem rust resistance gene with the same specificity as Sr21 and present in the Lr21 stock. Although he believed that recombination of Sr33 and Sr21 had occurred he was unable to confirm this because of possible meiotic instability in the amphiploid materials being examined. The study is being repeated using backcross derivatives. Preliminary results indicate a genetic distance of 4 cM between Sr33 and the Sr21 -like gene.