1958.1.2.4 Powdery Mildew Resistance
There are very few examples of variation for mildew resistance in Triticum
monococcum. A new powdery mildew resistant allele at the Pm4 locus was intro-
gressed from that species (Schmolke et al. 2012 ). Powdery mildew resistance was
found in one accession of T. urartu. Through conventional crossing and backcross-
ing a single dominant gene was transferred and mapped to chromosome 7AL (Qui
et al. 2005 ). The gene is temporarily designated as PmU. Two dominant and differ-
ent powdery mildew resistance genes, designated as Mlm 2033 and Mlm80, were
identifi ed in two different accessions of T. monococcum. They both mapped to chro-
mosome 7AL. Further tests indicated that they are probably allelic to each other and
mapped close to the Pm1 locus (Yao et al. 2007 ). Mildew resistance locus Pm1b was
transferred from T. monococcum to hexaploid wheat and mapped to chromosome
7AL (Hsam et al. 1998 ). Similarly Pm25 was introgressed from T. boeoticum into
hexaploid wheat and mapped to chromosome 1AL (Shi et al. 1998 ). Two powdery
mildew resistance genes from T. boeoticum were introgressed into bread wheat
(Chhuneja et al. 2012 ). They mapped to chromosome 7AL. One gene may be allelic
to Pm1 whereas the other is probably a new gene.
8.1.2.5 Fusarium Head Blight (FHB) Resistance
Fusarium head blight has now become a serious disease of cereals in all temperate
grain growing regions of the world. Effects of the disease are manifest as direct
yield reduction by kernel shrivelling plus the deposition of a vomitoxin in the seed
rendering it as a dangerous component in food and feed. One of the reasons for the
slow rate of progress in breading for resistance is the oligogenic control of resis-
tance. Additional genes/QTL for resistance are continually being sought, even
among wild species. Several reviews have been written on the identifi cation of
FHB resistance QTL in alien species (Cai et al. 2005 ). Triticum monococcum is
not listed in those reviews. T. monococcum was one of the species screened for
FHB resistance in our studies. To begin with, 200 accessions of T. monococcum
were obtained from M. Trottet of INRA. After repeated screening, line 10-1 was
identifi ed as having a fair level of FHB resistance (Fig. 8.2 ) (Fedak et al. 1997a , b ,
2003 ; Fedak 2000 ; 2007 ). Line 10-1 was crossed to the spring wheat cultivar AC
Domain. After repeated backcrossing and selection line M321 was selected. The
values for percent infected fl orets following point inoculation were 8 % as com-
pared to 4 % for the resistant check Sumai3, and 32 % for Roblin the susceptible
check. M321 was crossed to AC Domain and a doubled haploid mapping population
of 80 lines was produced by the maize pollination method (Fedak et al. 1997a , b ).
The population was phenotyped by point inoculation and genotyped with SSR
markers. A QTL for FHB resistance was located on chromosome 5A, linked to the
marker Xwme705 (Fedak et al. 2011 ).
The agronomic characteristic of M321 is listed in Table 8.2. Line M321 com-
pares favorably with check cultivars in terms of agronomic traits such as plant
8 Alien Introgressions from wild Tr it icu m species, T. monococcum...