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Legume Genomics and Genetics (online), 2010, Vol. 1, No.8, 41-46
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et al. (2004). The order and genetic distance between
the markers and
R
SC-12
were Sat_297 6.4 cM Sat_234
4.9 cM Sat_154 1.1 cM Satt114 0.7 cM SOYHSP176
1.6 cM Satt334 2.4 cM
R
SC-12
6.3cM Sct_033 (Figure 2).
Figure 2 The genetic linkage map of SMV resistance gene
R
SC
-
12
1.3 The MAS efficiency for the resistance gene
R
SC
-
12
The phenotype of F
2
, F
3
and F
4
populations were
identified by artificial inoculation, and the genotype of
each plant from F
2
, F
3
and F
4
was tested by the SSR
markers closely linked to
R
SC-12
, Satt334 and Sct_033.
The data obtained was used to evaluate the MAS
efficiency of
R
SC-12
by Satt334 and Sct_033 so as to
verify their reliability and practicability in MAS.
In the F
2
population, among the 164 plants showing
resistant phenotype after inoculation, 159 presented
resistant genotype tested by Satt334, and 155 presented
resistant genotype tested by Sct_033. The coincidental
rates were 97.0% and 94.5%, respectively. Of the 55
susceptible plants identified by inoculation, 54 showed
susceptible genotype by Satt334, and 49 displayed sus-
ceptible genotype by Sct_033. The coincidental rates
were 98.0% and 89.1%, respectively (Table 3). 153
resistant genotype plants tested by Satt334 and Sct_
033 were all resistant phenotype by inoculation, which
indicated that MAS efficiency for resistant plant by
Satt334 and Sct_033 was as high as 100% (Table 4).
Similarly, MAS efficiency for the resistance plants in
F
3
and F
4
populations were all more than 85% by
using either Satt334 or Sct_033 (Table 3), and up to
100% by the two markers co-used (Table 4).
This result indicated that the resistance of the plants
tested by the SSR markers Satt334 and Sct_033 showed
high consistency to the one by conventional inocu-
lation. Therefore, the two SSR markers can be used effect-
ttively in selecting for resistance gene
R
SC-12
instead of
inoculation identification.
2 Discussion
In present study, the resistance gene
R
SC-12
from Qi-
huang22 was located on linkage group F between the
SSR markers Satt334 and Sct_033. Interestingly,
Table 3 Coincidental rate between SSR detection and inoculation in F
2
, F
3
and F
4
population
Inoculation
Genotype tested by SSR
MAS efficiency
Population Marker
Total
Phenotype
No. of plants RR+Rr
rr
R(S) (%)
Mean (%)
R
164
159
5
97.0
Satt334
219
S
55
1
54
98.0
97.3
R
164
155
9
94.5
F
2
Sct_033
219
S
55
6
49
89.1
93.2
R
120
119
1
99.2
Satt334
192
S
72
0
72
100
99.5
R
120
114
6
95
F
3
Sct_033
192
S
72
8
64
88.9
92.7
R
94
94
0
100
Satt334
152
S
58
2
56
96.6
98.7
R
94
94
0
100
F
4
Sct_033
150
S
56
7
49
87.5
95.3
Table 4 MAS efficiency when two markers Satt334
-
Sct_033 flanking
R
SC-12
were co-used
Population No. of R plants No. of RR+Rr plants
Percentage of R
plants (%)
No. of S plants
No. of rr plants
Percentage of S
plants (%)
F
2
153
153
100
51
48
94.1
F
3
114
114
100
64
64
100
F
4
94
94
100
49
49
100
43