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Molecular Plant Breeding 2010, Vol.1 No.4
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Table 1 Chi-square text and genetic analysis of F
2
derived from the cross between CB033 and Huixianhong
Materials
Gene/Markers No. of F
2
No. of R/S
Expected ratio
χ
2
Genetic distance (cM)
R
S
F
2
(CB033/Hui
xianhong)
Pm21
213
153
60
3:1
1.401
Xcfe164
213
157
56
3:1
0.189
3.75
Xedm129
213
163
50
3:1
0.264
1.26
Xcinau188
213
163
50
3:1
0.264
0.98
Note: R: Genotype of the resisitant plant; S: Genotype of the suspectible plant; χ
2
0.05
=3.84, df=1
Figure 2 Linkage maps of the
Pm21
in the F
2
population
Figure 3 Amplification products by
Xcfe164
in resistant parent
CB033 (P1), susceptible parent Hui xianhong (P2), part
individuals of F
2
Note: R: Resistant plants; S: Suspectible plants; P1: CB033; P2:
Hui xianhong; V:
Haynaldia villosa
; M: DL2000 marker
1.4 Verification of molecular markers
In order to validate
Xcfe164
,
Xcinau188
and
Xedm129
were reliability, the homozygous resistant and
homozygous susceptible plants which were selected
from the F
2
segregation population by Codominant
marker NAU/XiBao15
-
902 (Cao et al., 2006) were
planted into the F
2:3
families to further resistance
identification and
molecular markers verification.
Results show that, in the investigation of F
2:3
families
(130 individuals), 62 homozygous resistant plants
showed immunity to powdery mildew, then 68
susceptible plants showed infection (Figure 4); the
three markers also could amplify the corresponding
marker band. So it proved that the three markers were
reliable. Part F
2:3
families plants of the PCR results
(Figure 5A, Figure 5B).
2 Discussion
As EST were the sequence of the cloned gene
fragments which were selected from the cDNA library,
and STS which were based on fragments of single
copy DNA sequences at both ends of specific primers
and amplified specific sequences, could be directly
obtained gene expression information, so the EST-SSR
and STS markers were reliable. In this study, we got
two EST-SSR markers
(
Xcfe164
,
Xedm129
) and one
STS markers (
Xcnau188
), enriched
Pm21
markers system.
Figure 4 Resistant performance of CB033 and hui xianghong’
derivetives
Note: A: Susceptible plant; B: Resistant plant
Figure 5 Amplification products by
Xcinau188
in resistant
parent Line CB033 (P1), susceptible parent Hui xianhong (P2),
part pure resistant individuals of F
2:3
Note: R: Resistant plants; S: Suspectible plants; P1: CB033; P2:
Hui xianhong; V:
Haynaldia villosa
; M: DL2000 marker