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Molecular Plant Breeding 2011, Vol.2, No.10, 68
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explain phenotypic variance ranged from 6.98 to
38.30% (Table 3; Figure 2). The additive effects for
five QTLs were positive, with increasing effects
coming from Chuan 35050. The additive effects of the
other five QTLs were negative, with increasing effects
coming from Shannong 483. The maltose content
QTL,
qMac
-
2D
-
1
, showed the highest contribution to
phenotypic variation (38.30%). This QTL was a major
QTL, and the increasing effect was from Shannong
483.
Table 3 Additive QTLs for water-soluble saccharide contents of RILs
Traits
QTL
Marker interval
Site
(cM)
LOD
Additive
effect
Contributions (%)
Total contribu-
tion (%)
Sucrose content
qSuc-1B-1
Xubc834b-Xubc880d
2
4.32
-
0.111
18.09
49.30
qSuc-2B-1
Xwmc154b-Xwmc154a
1
2.92
0.092
12.43
qSuc-3B-1
Xubc834a-Xwmc3a
13
2.81
-
0.082
9.82
qSuc-4A-1
Xswes620-Xswes615
0
3.30
0.078
8.96
Maltose content
qMac-1B-1
Xswes579-Xswes953
3
4.61
-
0.188
19.71
79.39
qMac-1D-1
Xwmc432a-Xwmc336c
3
3.85
0.161
14.41
qMac-2D-1
Xgwm261a-Xgwm296b
4
4.32
-
0.263
38.30
qMac-5D-1
Xswes558a-Xswes555a
2
2.56
0.112
6.98
Raffinose content
qRac-5A-1
Xgwm293-Xissr32a
9
3.54
-
0.188
14.32
25.65
qRac-6B-1
Xwmc487-Xwmc737
26
2.70
0.161
11.33
Note: “Marker interval” indicates the two markers either side of each QTL; “Site” is the distance of the LOD peak value for the QTL
from the first marker in “marker interval”; “Additive effect”: Negative values indicate that increasing effect was from Shannong 483,
positive values indicate that increasing effect was from Chuan 35050
1.2.1 Sucrose content
Four QTLs for sucrose content were detected on
chromosomes 1B, 2B, 3B, and 4A. Their total
contribution was 49.30% (Table 3). The effects of
qSuc
-
2B
-
1
and
qSuc
-
4A
-
1
on sucrose content were
positive, with increasing effects coming from Chuan
35050. The effects of
qSuc
-
1B
-
1
and
qSuc
-
3B
-
1
on
sucrose content were negative with increasing effects
coming from Shannong 483. The contribution of
qSuc
-
1B
-
1
was 18.09% which was highest among the
four QTLs.
1.2.2 Maltose content
Four QTLs for maltose content (total contribution,
79.39%) were also found on chromosomes 1B, 1D,
2D and 5D. The positive effects of
qMac
-
1D
-
1
and
qMac
-
5D
-
1
mainly came from Chuan 35050 while
the negative effects of
qMac-1B-1
and
qMac-2D-1
came from Shannong 483. Of these four QTLs,
qMa
c-2D-1
made the greatest contribution(38.30%) to
phenotypic variation in maltose content, and
qMac-
1B-1
and
qMac-1D-1
also made significant contribu
tions (19.71 and 14.41%, respectively).
1.2.3 Raffinose content
Two QTLs for raffinose content,
qRac-5A-1
and
qR
ac-6B-1
, were located on chromosomes 5A and 6B,
with a total contribution of 25.65% (Table 3; Figure 2).
The effect of
qRac-6B-1
was positive with the
increasing effect contributed by Chuan 35050. The
effect of
qRac-5A-1
was negative with the increasing
effect contributed by Shannong 483. The contributions
of
qRac-5A-1
and
qRac-6B-1
to phenotypic variations in
raffinose contents were 14.32 and 11.33%, respectively.
2 Discussions
QTL analyses have been used to study fructan content
in wheat grains (Huynh et al., 2008). However, to our
knowledge, there have been no QTL analyses of
water-soluble oligosaccharide contents. Using a ChSh
population, we detected 10 additive QTLs for sucrose,
maltose, and raffinose contents of wheat grains. Single
QTLs for sucrose and maltose contents were located
on 1B, while the other QTLs were located on different
chromosomes. This result indicates that the traits tend
to be distributed among all the chromosomes.