Sr22

Kerber, E.R., and P.L. Dyck. "Inheritance of stem rust resistance transferred from diploid wheat (Triticum monocooum) to tetraploid and exaploid wheat and chromosome location of the gene involved." Canadian Journal of Genetics and Cytology 15: 397-409.

Chromosome Location

7A (Kerber and Dyck, 1973); 7AL . Sr22 is located 30 cM from the centromere, 2 cM from cn-A1 (chlorina phenotype) and more than 50 cM proximal to Pm1/Lr20/Sr15 (The and McIntosh, 1975).

Low Infection Type

; (in diploid wheat) to 2- (in hexaploid wheat) (Kerber and Dyck, 1973); 1- to 2 (Huerta-Espino, 1992).

Environmental Variability

Temperature sensitive; more effective at lower temperatures.

Origin

T. monococcum R.L.5244 (Kerber and Dyck, 1973; The, 1973a). The (1973b) found that Sr22 was present in a range of wild einkorn wheats.

Pathogenic Variability

Virulent cultures were not detected in surveys in Mexico (Singh, 1991), USA (Roelfs and McVey, 1979), South Africa (Le Roux and Rijkenberg, 1987a) and Australia (Zwer et al., 1992). Huerta-Espino (1992) also failed to detect virulence in his international survey. However, Gerechter-Amitai et al. (1971) reported virulence in ten of 12 pathotypes used in Israel.

Reference Stocks

i: Sr22/9*LMPG (Knott, 1990).

v: Chinese Spring/3/Steinwedel*2//Spelmar/T. boeoticum G-21 (The, 1973a); Marquis*5//Stewart*3/T. monococcum R.L.5244 (Kerber and Dyck, 1973; The, 1973a); Steinwedel*2//Spelmar2*/T. boeoticum G-21 (The, 1973a).

tv: Spelmar*2/T. boeoticum G-21 (Gerechter-Amitai et al., 1971; The, 1973a); Stewart*6/ T. monococcum R.L.5244 (Kerber and Dyck, 1973).

dv: Various T. monococcum accessions including G-21 and R.L.5244 (Kerber and Dyck, 1973; The, 1973a, 1973b).

Source Stocks

Australia: BT-Schomburgk; Schomburgk.

 

Seedling leaves of (L to R): T. monococcum C68.114 (2n = 14), Glossy Huguenot*2/ T. monococcum C85.105 (2n = 28), Marquis*5//Stewart*3/ T. monococcum R.L.5244 (2n = 42) and Marquis; infected with pt. 21-1, 2 and incubated at A. 18°C and B. 23/28°C. Note the distinctly higher response of the third (hexaploid) line at the higher temperature. On the other hand, the second (tetraploid) line appears to be more resistant at the higher temperature.

 

Use in Agriculture

Cultivar Schomburgk was released in Australia in 1986. This and a boron-tolerant derivative, BT-Schomburgk are the only commercial cultivars with this gene. Lines carrying Sr22 were reported to be moderately susceptible in the field by Roelfs and McVey (1979).