Distally located in 6AL (McIntosh, 1972).
Low Infection Type
1, 11+, 2- to 23-. 2- at 30°C and 2+3 at 18°C (Roelfs and McVey, 1979).
Lowest infection types are obtained at temperatures of 20-28°C, that is, the higher temperature range used for seedling tests.
T. turgidum var. dicoccum cv. Khapli C.I.4013 in the differential set of Stakman et al. (1962). Sr13 was transferred to the common wheat line, Khapstein by WL Waterhouse.
Virulence for Sr13 appears to be extremely rare except in India and Pakistan (Luig, 1983) where Khapli emmer is cultivated. Occasional cultures from Europe and Africa produced high infection types on Khapstein (Luig, 1983). Knott (1990) reported a virulent culture of North American race 11. Huerta-Espino (1992) detected one isolate with virulence in Ethiopian samples, one in Turkish and two in Spanish collections.
v: Khapstein Sr2 Sr7a Sr14 (Knott, 1962b).
tv: Khapli emmer Sr7a Sr14.
Australia: Wialki (Luig, 1983). Madden Sr2 Sr9b Sr11 (Luig, 1983).
Europe: French Peace Sr7a Sr9a (Knott, 1983).
tv: St464. Probably present in some durums especially those derived from St464.
|Seedling leaves of (L to R): Khapli emmer, Khapstein, Marquis + Sr13 (= Khapstein/10*Marquis) and Marquis; infected with pt. 34-1, 2, 3, 6, 7, 8, 9 and incubated at A. 23/28°C, and B. and C. at 18°C. B. and C. show the lower and upper leaf surfaces, respectively. Sr13 was ineffective at the lower temperature. Both Khapli and Khapstein possess genes additional to Sr13 and some interactions involving Sr13 are evident, especially necrosis associated with Sr14.|
Use in Agriculture
Because of its widespread effectiveness, Sr13 is potentially useful as a source of resistance to stem rust and has been exploited in some Australian wheats. However, RA McIntosh, RG Rees and GJ Platz (unpublished, 1985) showed that wheats with Sr13 expressed comparatively high adult plant reactions to avirulent cultures and experienced grain weight losses of about 40% relative to chemically protected controls. Related lines lacking the Sr13 allele gave much higher losses. The origin of Sr2 (RA McIntosh, unpublished 1980) and Sr7a (Knott, 1962b) in Khapstein must be questioned because neither gene has been reported in Khapli. In his early studies on hexaploid/tetraploid wheat crosses Waterhouse (1933) reported that cv. Steinwedel and its derivatives were the only hexaploids not producing chlorotic (hybrid chlorosis) hybrids with Khapli. Sterility in pentaploids may have led to outcrossing and Sr2 and Sr7a may be derived from other sources. RA McIntosh (unpublished, 1985) showed that a gene (Srdp2) in a Golden Ball-derived hexaploid wheat, accession W3504, was allelic with Sr13.