193was found that of 1062 gene bank accessions of T. monococcum , 78.7 % was found
to be resistant to TTKSK (Ug99) and four of its variants (Rouse and Jin 2011b ).
Some accessions were resistant to multiple races. Genetic tests were conducted with
some of the resistant accessions (Rouse and Jin 2011b ). They found two genes with
resistance to TTKSK that were different from Sr21 , Sr22 and Sr35. One of the
accessions was resistant to all races tested.
205 gene bank accessions of T. urartu were screened for resistance to TTKSK
and some of its variants. It was found that 93 % of the accessions were resistant to
TTKSK (Rouse and Jin 2011a ). The observed resistance is likely due to new genes.
Thus far no stem rust resistance genes have been introgressed into wheat from T.
urartu. In earlier screening studies, 102 accessions of T. monococcum were screened
with 2 Italian races of stem rust and 48 and 60 % of accessions were resistant
(Vallega 1979 ). A new stem rust resistance gene from T. monococcum has been
transferred to hexaploid wheat (Valkoun et al. 1989 ). On a much smaller scale, in
testing of 10 accession of T. monococcum obtained of from M. Trottet of INRA, one
line was found to carry unique genes for resistance to TTKSK (Fedak 2000 ).
8.1.2.2 Leaf Rust Resistance
Triticum monococcum has not made a signifi cant contribution to leaf rust resistance
to date, however there appears to be considerable potential for a source of leaf rust
resistance genes. For example Vallega ( 1979 ) screened up to 102 accessions of
T. monococcum with fi ve different accessions of leaf rust and all accessions were
resistant to all races. A study of 49 accessions in the University of Saskatchewan
collection revealed 2 independent dominant genes for leaf rust resistance (Bai et al.
1998 ). Two accessions were also shown to carry Sr22 and Sr35 for stem rust resis-
tance. Triticum monococcum accession number 14087 was shown to have resistance
to leaf rust at the seedling and adult plant stage plus adult plant resistance to stripe
rust (Dhaliwal et al. 2005 ). Resistance to leaf rust, stripe rust, and karnal bunt was
subsequently transferred to hexaploid wheat. Prehaustorial resistance to the leaf rust
fungus, Puccinia triticina has been detected in some accessions of T. monococcum
(Anker and Niks 2001 ). This is a non-hypersensitive reaction and acts before the
formation of the haustoria by the fungus. In this study, 84 % of 182 accessions of T.
monococcum were found to be resistant to leaf rust, but only three showed prehaus-
torial resistance. A number of leaf and stripe rust resistance genes have been mapped
in T. monococcum and transferred to bread wheat (Singh et al. 2007a ). A dominant
gene for leaf rust resistance was introgressed from T. monococcum to hexaploid
wheat and located on chromosome 3A (Valkoun et al. 1986 ). One leaf rust resis-
tance gene from T. monococcum var. monococcum and two from T. monococcum
var. boeoticum were transferred to hexaploid wheat and their race specifi cities were
confi rmed (Hussein et al. 1997 ). The gene Lr63 from T. monococcum was intro-
gressed onto chromosome 3AS of hexaploid wheat (Kolmer et al. 2010 ).
A large number of accessions of diploid and tetraploid wheats were screened for
resistance to a number of insects and fungal pathogens (Gill et al. 1983 ). Sixty eight
8 Alien Introgressions from wild Tr it icu m species, T. monococcum...