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resistance. Interestingly, in the results by von der
Ohe (2010), the 5A QTL had a larger resistance-
improving effect, whereas Samaleh et al. (2011)
found a larger effect of the 3B QTL. The final
resistance level of the derived lines depended to
a large extent on the background resistance of
the recurrent parent. For example, incorporat-
ing resistance QTL into a moderately resistant
cultivar led to highly resistant progeny; incorpo-
rating the QTL into a highly susceptible culti-
var improved this to a moderately susceptible
line. There was no systematic negative effect
of the spring-wheat-derived QTL on yield and
other agronomic traits. Some resistant lines with
spring wheat QTL alleles were equal to or even
slightly better in yield than the recurrent culti-
vars. All in all, these results underscore the fact
that utilization of exotic QTL is highly promis-
ing when a rigorous backcrossing and selec-
tion scheme is applied. Markers are a perfect
tool to select the desired genotypes quickly and
efficiently.
combined expressed 36% reduced FHB sever-
ity compared to lines with the Lynx alleles.
At the same time, both QTL were associated
with increased plant height. Wilde et al. (2008)
explored marker-based selection, and Miedaner
et al. (2009) compared marker-based selection to
phenotypic selection. They used an experimen-
tal population entirely based in European winter
wheat. A population of 600 progeny was derived
from a double-cross combining three FHB resis-
tance QTL alleles (6AL and 7BS from the cul-
tivar Dream and one QTL on chromosome 2BL
from the line G16-92) with two high-yielding,
susceptible winter wheat varieties. Both marker-
based selection and phenotypic selection led to
a selection response toward increased resistance.
Total gain by selection was larger in phenotyp-
ically selected variant, but resistance gain per
unit time was larger in the marker-selected vari-
ant. The allele substitution effect of the QTL in
this MAS project was lower compared to the esti-
mated effects of the QTL alleles in the preceding
mapping projects.
Haberle et al. (2009) validated an FHB resis-
tance QTL on chromosome arm 1BL descending
from the German cultivar Cansas in F
4
-derived
sister lines that increased FHB resistance by 42%
compared to lines lacking the positive allele.
Marker-assisted breeding using well-validated
QTL detected in European winter wheat thus
appeared as effective as marker-assisted breed-
ing for exotic QTL from Asian spring wheat
sources.
MAS for FHB Resistance QTL
Available in European Winter
Wheat
To date, only a few reports applying marker-
assisted selection for FHB resistance QTL of
non-Asian origin are available (Haberle et al.
2007, 2009; Wilde et al. 2008; Miedaner et al.
2009). The potential advantage in using so-called
native resistance, as opposed to exotic resistance
sources, is that regionally adapted breeding lines
can be selected easier and faster, because fewer
rounds of crossing and selection are needed in
order to select agronomically acceptable vari-
eties. Three reports are based on the FHB-
resistant German winter wheat variety Dream,
with previously mapped QTL at chromosome
arms 6BL, 7BS, and 2BL (Schmolke et al.
2005). Haberle et al. (2007) selected BC
2
F
4
lines for the QTL at 6BL and 7BS using the
susceptible cultivar Lynx as recurrent parent.
Lines with individual QTL expressed about 27%
reduced FHB severity and lines with both QTL
MAS for Improving FHB
Resistance in Tetraploid Wheat
Because durum wheat is highly FHB suscep-
tible, and only little genetic variation for this
trait is available in durum wheat, it appeared
logical to introgress QTL from bread wheat
to durum wheat. It is easy to transfer A
and B genome chromosome segments between
these species by crossing and selection, but
the progeny thus attained was not necessar-
ily
better
in
resistance.
Yet,
among
about
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