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MABS based selection of high O/L ratio individuals in peanut
Table 11.1.
Homozygous
backcrossing ratio
c
Homozygous
backcrossing rati
c
of
the selected individuals
Number of
individuals
of FAD2/YI
genotypes
b
of
Number of
selected
individuals
a
Number of
used GW
markers
the all individuals
Number of all
individuals
Generation
Average
Range
Average
Range
F
1
58
34
-
1
-
-
-
-
F
2
204
3
7
-
-
-
-
-
F
3
12
-
-
-
-
-
-
-
BC
1
F
1
108
12
-
42
55.4
38.5-69.2
62.9
52.6-68.4
BC
1
F
2
178
8
16
19
62.9
33.3-93.3
70.2
53.3-80.0
BC
2
F
1
26
10
-
34
83.5
73.5-91.2
87.9
85.3-91.2
BC
2
F
2
205
9
9
-
-
-
-
-
a
Individuals were selected based on genotypes of
FA D 2
loci, GW markers and phenotypes.
b
Number of individuals showing homozygous 'YI-0311' genotypes on
ahFAD2A
and
ahFAD2B
genes.
c
Ratio of markers showing homozygous 'Nakateyutaka' genotypes to all the tested GW markers.
GW DNA Markers
was homogenized using TissueLyzer (Qiagen,
Hilden, Germany). The other parts of the seeds
were sown in pots to obtain an F
3
generation.
The homogenate was used for determination of
fatty acid content. The quantification was per-
formed using a GC-TOF-MS system consisting
of a 6890N Network GC System (Agilent Tech-
nologies, U.S.A.) equipped with a DB-17MS
column (30 m, I.D 0.25 mm, film 0.25 μm) (J&W
Scientific, U.S.A.), coupled to Pegasus3 (Leco
R
The presence of selfing seeds in the F
1
generation
was investigated using a simple sequence repeat
(SSR) marker, PM204 (He et al. 2003). When the
breeding program was started in 2007, only a few
DNA markers showing polymorphisms between
'Nakateyutaka' and 'YI-0311' had been devel-
oped. Accordingly, we developed GW poly-
morphic markers and a linkage map in paral-
lel with the breeding program (Koilkonda et al.
2011; Shirasawa et al. 2012). A total of 19-42
polymorphic SSR and transposon markers were
used to assess GW genotypes in BC
1
F
1
,BC
1
F
2
and BC
2
F
1
progenies (Table 11.1). The GW
DNA markers had not been mapped on a peanut
linkage map until 2011 and the positions of the
markers on the genome were therefore unknown
when the genotypes were investigated.
,
St. Joseph, MI, U.S.A.). Acquisition and analy-
sis of mass spectrometry data were performed
using ChromaTOFTM version 2.32 optimized
for Pegasus (Leco
R
). The concentrations of oleic
acid, linoleic acid, palmitic acid, and stearic acid
were estimated from calibration curves obtained
using the respective pure compound. The associ-
ation between O/L ratio and genotypes on the two
FA D 2
loci was detected with Genotype Matrix
Mapping software and the following parame-
ters: Max Length of Locus Combination
Investigation of Fatty Acid Content
in Seeds
=
2; Min
Number of Corresponding Samples
=
1; Search
Range
=
auto (Isobe et al. 2007).
The selected 32 F
1
parents and the two parental
lines were sown in a peanut plant breeding
field of the Chiba Prefectural Agriculture and
Forestry Research Center in May 2008. The F
2
and the parental seeds were harvested in Octo-
ber and dried with shells for one month under
open air conditions. One quarter of each dried
seed was cut off, and 25 mg of seed material
Results and Discussion
Association between FAD2 Genes
and O/L Ratio
Four fatty acid compounds were identified in
seeds
including
palmitic,
stearic,
oleic,
and
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