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Legume Genomics and Genetics 2012, Vol.3, No.3, 14
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15
of 2.9 cM. In 2008, they confirmed that this QTL was
located between Sat_093 and Sat_366 on chromosome
16 using soybeans from 4 different genetic backgounds,
which accounted for 50% of the total variance. They
also found that the allelic gene controlling PD has
multiple-bit points in different genetic backgrounds
(Funatsuki et al., 2008). Suzuki et al (2010) thought
that
qPDH1
controls the process of PD in soybean,
while the morphological characteristics of soybean
didn’t relate to this process. Yamada et al (2009)
analyzed the PD among several soybean populations,
and they found that there were differences among the
PD controlling genes in different genetic backgrounds,
but
qPDH1
was still the gene responsible for controlling
PD. Kang et al., (2009) identified one major QTL and
three minor QTLs for PD, which were located on
chromosome 6, chromosome 5, chromosome14 and
chromosome 10, respectively. The major QTL was
located near to
qPDH1
. They also found that PD
controlling genes have some differences in different
genetic backgrounds.
In this study, we used the RILs population (JINF
population) constructed by our laboratory and Shanxi
Academy of Agricultural Sciences (Liu et al., 2003) to
perform QTL mapping and correlation analysis on PD
and 2 other related traits, namely days of full maturity
(DFM) and Ratios of thickness to width (RTW) so that
we can understand the relationship between PD trait
and other related traits. This will help lay down the
foundations for future application on gene cloning and
molecular breeding.
1 Results and Analysis
1.1 Correlation analysis among the three related
traits
We surveyed the phenotypic evaluations of PD, days
of full maturity (DFM), ratio of thickness to width
(RTW) in 112 strains of soybean JINF population,
and we analyzed the correlation analysis of these
three related traits with SPSS 16.0. The results
demonstrated that there was a certain negative correlation
between PD and the DFM and RTW, an extremely
significant negative correlation between PD and RTW
(P=0.01,
-
0.960), and a significant negative correlation
between PD and DFM (P=0.05,
-
0.740). Nevertheless,
there was a significant positive correlation between
RTW and DFM (P=0.05, 0.867).
1.2 QTL mapping of PD
We identified the QTL location for the PD in 112
soybean strains of JINF population by the composite
interval mapping (CIM) method in WinQTLCart 2.5.
Set the LOD value>2.0. We obtained a QTL for the
PD, designated as
qPDH6
-
1
, which was located in the
region between Sat_062 and Satt520 on the linkage
group C2 (Chromosome 6) with LOD value 12.15,
genetic distance of 3.1 cM, and 49.44% of the total
variance accounted for (Figure 1; Table 1).
1.3 QTL mapping of RTW
Three QTLs location were identified for the RTW in 112
soybean strains of JINF population by the composite
interval mapping (CIM) method in WinQTLCart 2.5,
which were designated as
qRTW11
-
1
,
qRTW4
-
1
and
qRTW8
-
1
, respectively (Figure 2; Table 1).
qRTW11
-
1
was located in the region between Satt426
and 9.03% of the total variance accounted for.
qRTW4
-
1
was located in the region between Satt361
and Satt399 on the LG C1 (chromosome 4) with LOD
value 2.77 and genetic distance of 0.4 cM, and it could
account for 8.20% of the total variance.
qRTW8
-
1
was
located in the region between satt187 and Satt377 on
Table 1 The information about QTLs of PD, RTW and DFM in the JINF RIL population
Traits
QTL Locus
Chr./position
(cM)
The marker closest
to the QTL
LOD value
Genetic
distance (cM)
Additive
R
2
(%)
Pod dehiscence (PDH)
qPDH6
-
1
6/2.01
Sat_062
12.15
3.10
-
2.750
49.44
Ratio of thickness to
width (RTW)
qRTW11
-
1
11/0.03
Satt426
3.00
10.00
-
0.014
9.03
qRTW4
-
1
4/52.01
Satt361
2.77
0.40
0.013
8.20
qRTW8
-
1
8/31.21
Satt187
2.14
3.70
0.012
7.02
Days of full maturity
(DFM)
qDFM6
-
1
6/0.05
Sat_062
6.59
7.20
2.570
21.77
qDFM6
-
2
6/22.51
Satt291
2.85
12.30
1.600
9.74
qDFM18
-
1
18/42.91
Satt217
2.81
0.60
1.440
7.74