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Genomics and Applied Biology, 2011, Vol.2 No.6
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donor happened in three genetic backgrounds. In the
context of T78, the traits with the most significant
differences were plant height and a number of the
primary (first) branches, there were four lines with
significant or very significant differences, whereas the
traits of the lines with little difference were the
thickness of stem and a number of silique of primary
branches, which were no significant differences with
the donor’s background of T78. The candidate lines
with high genetic similarity with the donor of T78
were the lines of wh15, wh14 and wh13, comparing to
the donor of T78, the line of wh15 only had significantly
difference in the trait of branching point height, the
wh13 in the traits of plant height and branching point
height as well as the wh14 in the traits of the branching
point height and the length principal inflorescence. In
the context of T84, the traits with the most significant
differences were plant height and branching point
height, there were six lines with significant differences
comparing to the parents, while there was no significant
difference in the traits except the number of the
second branch and the length of silique. The candidate
lines with high genetic similarity with the donor of
T84 were the lines of wh59 and wh78, which had
significant difference in the trait of plant height and
the branching point height comparing to the donor of
T84. In the context of ZS9, the traits with the most
significant differences were plant height and the
branching point height, there were six and seven lines
with significant differences, respectively, whereas the
traits of the lines with little difference were the number
of primary branch, the number of silique in principal
inflorescence, the number of silique in primary branch,
the length of silique, the number of seed per silique
and 1000-seed weight. The candidate lines with high
genetic similarity with the donor of ZS9 were the lines
of wh118 and wh127 sequentially, which had significant
difference in the trait of plant height and the branching
point height comparing to the donor of ZS9. In terms
of the comparison among three genetic background
germplasms and their derived lines, there were eight
traits with no significant differences in the candidates
with T84 background, only two traits with no significant
differences in the candidates with T78 background,
while six traits with no significant differences in the
candidates with ZS9 background. Therefore, the
candidates of near-isogenic lines with T84 and ZS9
background had overall higher allelism than that of
the candidates with T78 background based on the
genetic similarity of agronomic traits.
1.3 Molecular identification of NIL candidates
NIL candidates derived from three genetic background
of MI CMS system restore gene were identified by
using 75 of SSR primer pairs. The results showed that
total of 157 target bands in size from 100 bp to 500 bp
were amplified by using 75 pairs of primers, each pair
of primers amplified an average of 2.3 bands. There
were 11 pairs, 4 pairs and 2 pairs respectively to
generate only one polymorphic band in their genetic
backgrounds. Figure 1 showed the banding pattern
amplified in the three genetic backgrounds by the
primer of H33. The results further indicated: (1) the
same primer might come out with different amplification
results in the same genetic background. Primers H33
generated clear 4 bands with different sizes in the T78
background, while only 2 bands in the T84 background
as well as only one similar size band in ZS9 background.
(2) Generally, all lines derived from the same
background go to the same as the amplified results of
each line, but the difference might happen, while the
difference used as criteria for measuring the allelism
of NILs. In the T78 background, all lines were
consistent with the amplification results by H33,
whereas in the T84 background, all lines had the same
result of the band in size of about 200 bp, but the
difference of the band in size about 450 bp. The
banding patterns were quite different between lines of
9, 10, 15 and lines of 11, 12 and 13. In the ZS9
background, the banding pattern with a continuous
bands in size amplified, which were the same in the
lines of 16, 18, 22 and 17 while different in the line of
19, 20, 21, 23 and 24 (Figure 2).
Figure 2 The banding pattern amplified by the primer H33 in
24 lines of three genetic backgrounds
Note: M: DL1000 marker; 1~24: The number of candidate NILs
and three genetic background germplasms, as indicated in table 1