209One of the genes was identical to Pm2. The other was a unique gene located on
chromosome 2BL and designated as Pm6 (Jorgensen and Jensen 1973 ). Pm6 has
since been mapped to chromosome 2BL with DNA markers. The linked marker
BCD135 has been used to detect Pm6 in various backgrounds (Tao et al. 2000 ).
According to Dhaliwal et al. ( 1993 ) the T. timopheevii derived mildew resistance
gene Pm6 was transferred to hexaploid wheat.
8.3.1.4 Fusarium Head Blight Resistance
Fusarium head blight resistance was discovered in accession PI 343447 of T.
timopheevii (Cao et al. 2009 ). This accession was crossed as a pollen parent to the
variety Crocus which has the three crossability genes Kr1 , Kr2 , Kr3 (dominant Kr
genes). The F1 and BC1 embryos were excised and raised on an artifi cial medium.
A population of 535 BC1F7 lines were established by SSD. One hundred lines were
selected from this population based on plant fertility and agronomic traits. The lines
were evaluated for the FHB reaction in fi eld and greenhouse trials in four replicates
and two seasons. From this trial line TC67 was selected, based on its superiority in
FHB reaction and agronomic traits (Fig. 8.5 ) (Table 8.7 ).
Fig. 8.5 Resistance to
Fusarium head blight
expressed in TC67 an
introgression from
T. timopheevii. Disease
symptoms expressed
at 21 days after
inoculation. Roblin is
the susceptible check
8 Alien Introgressions from wild Tr it icu m species, T. monococcum...