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Molecular Plant Breeding 2012, Vol.3, No.8, 80
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Table 1 Distribution of crown rot severity in the four wheat validation populations
Crosses
Populations
No. of lines
Parents
Populations
R-parent
S-parent
Min.
Max.
Mean
SD
27868/Ernie
F4/F5
67
1.23
3.20
0.83
3.79
2.25
0.68
13832/Ernie
F4/F5
120
1.17
3.45
1.05
3.57
2.17
0.47
Kennedy/Ernie
DH
55
1.44
3.78
1.27
4.15
2.80
0.52
10903/Ernie
F2/F3
120
0.95
2.97
0.78
3.34
2.10
0.70
Table 2 Effects of the 3B crown rot QTL in four wheat validation populations
Crosses
Associated markers
Validation of the effects of the crown rot-associated markers
RR
rr
Effects (%)
P value
27868/Ernie
gwm0181
1.15
2.1
45.2
<0.01
13832/Ernie
gwm0181
1.27
2.5
47.3
<0.01
Kennedy/Ernie
gwm0181
1.38
3.56
61.2
<0.05
10903/Ernie
wmc0471
2.09
3.31
36.7
<0.01
Table 3 Distribution of crown rot severity in the three barley validation populations
Crosses
Populations
No. of lines
Parents
Populations
R-parent
S-parent
Min.
Max.
Mean
SD
TX9425/Naso Nijo
DH
74
1.76
3.71
1.51
4.03
2.40
0.6
TX9425/Gairdner
F3/F4
120
1.19
3.23
0.97
3.95
2.23
0.58
TX9425/DYSYH
F3/F4
119
1.53
2.97
1.24
3.78
2.70
0.7
Table 4 Effects of the 3H crown rot QTL in three barley validation populations
Crosses
Associated markers
Validation of the effects of the crown rot-associated markers
RR
rr
Effects (%)
P value
TX9425/Naso Nijo
Bmac0209
1.74
3.21
45.8
<0.01
TX9425/Gairdner
HVM33
1.36
2.40
41.7
<0.01
TX9425/DYSYH
HVM33
1.20
2.71
55.4
<0.01
2 Discussion
2.1 The potentiality of using the CR loci in wheat
and barley breeding practice
Both wheat and barley can be seriously affected by
CR disease (Wildermuth and Purss, 1971). Extensive
genetic studies on CR have been carried out in bread
wheat and several loci conferring CR resistance have
been reported for bread wheat, and were located on
chromosomes 4B (Wallwork et al., 2004), 1A and 1D
(Collard et al., 2005), and 2B, 2D, and 5D (Bovill et
al., 2006). However, the effect of these reported QTL
was not stable and none of them reached significant
levels in all of the trials conducted in the related study.
This makes it very hard for breeders to incorporate
CR resistance from these reported sources into
commercial varieties and to track down the resistance
genes in the progenies derived from these sources.
Fortunately, recent studies have identified a major
QTL on the long arm of chromosome 3B conferring
CR resistance in three different wheat genotypes, two
of them belong to
T. aestivum
(Li et al., 2010a; Bovill
et al., 2010), another belong to
T. spelta
(Ma et al.,
2010). The magnitude of the 3B CR QTL identified in
the wheat genotypes ‘Ernie’ and ‘CSCR6’ explained
up to 34.6% and 46.2% of the phenotypic variance
with detection in each of the trials with the use of two
different
F. pseudograminearum
and
F. graminearum