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Steinwedel (a soft white wheat) and T. timopheevii. Allard ( 1949 ), provided detailed
cytogenetic studies of progenies of wheat and T. timopheevii hybrids in the process
of transfer of disease resistance to hexaploid wheat. In addition to resistance to stem
rust and mildew in his progenies, Allard ( 1949 ) also reported bunt resistance.
Subsequent screening results report a high frequency of accessions carrying
resistance to six different pests. A total of 301 accessions of T. timopheevii var.
araraticum were screened for resistance to leaf rust, stem rust, stripe rust, powdery
mildew, tan spot, wheat curl mite, and Hessian fl y (Brown-Guedira et al. 1996 ).
A large number of accessions were recognized with R ratings for fi ve of the pests.
For stripe rust, only MR levels were observed.
8.3.1 Disease Resistance
8.3.1.1 Stem Rust Resistance
Three wheat lines with stem rust derived from T. timopheevii have been reported.
One strain was CI12632 (W1656) with resistance introgressed to chromosome 2B
(Nyquist 1957 ). Line W (W3563) was derived from selections in W1906/ T.
timopheevii W 1899/2/3 Steinwedel W199 (McIntosh and Gyarfas 1971 ). CI 13005
was another T. timopheevii -derived line that gave moderate resistance to race 15B
(Atkins 1967 ). Timopheevii with stem rust resistance is another wheat strain derived
from T. timopheevii (Watson and Luig 1958 ). In a subsequent report the timopheevii-
derived lines CI 12632 and CI 12633 were described as having adult plant resis-
tance to leaf rust, stem rust and mildew (Allard and Shands 1954 ). CI12633 was
also reported to be highly resistant to loose smut (Table 8.6 ). The timopheevii
wheats were screened for resistance to rusts and powdery mildew and variability for
both traits was observed (Tomar et al. 1988 ).
8.3.1.2 Leaf Rust Resistance
A QTL for adult plant leaf rust resistance was transferred to wheat from a synthetic
allopolyploid derived from T. timopheevii / T. tauschii. The gene originated in chro-
mosome 2G and was mapped to chromosome 2B with microsatellite markers.
It explained 31 % of the total variance (Leonova et al. 2007 ).
8.3.1.3 Powdery Mildew
Powdery mildew resistant gene Pm27 was introgressed from chromosome 6G, of
T. timopheevii elite wheat and mapped to chromosome 6BL by RFLP and micro-
satellite analysis (Järve et al. 2000 ). Two unlinked dominant genes for mildew
resistance were introgressed from T. timopheevii into winter wheat line TP114.
G. Fedak