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Rice Genomics and Genetics 2012, Vol.3, No.4, 19
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al., 2009), quality improvement (Li et al., 2004; Xia et
al., 2004), restorer line breeding (Chen et al., 2009;
Xue et al., 1998)in china by using marker-assisted
selection. With the rapid development of molecular
biology technology, more and more important agronomic
traits in rice genes were localized, some tightly linked
molecular markers of these traits have been screened .
Adopting these molecular markers for indirect
selection, we will get a multiplier effect. However, so
far, there are still little new rice varieties (lines)
developed via molecular marker-assisted selection.
Considering the reasons, maybe one is that the main
effect gene is not much among the important traits in
the positioned rice, and the genes for auxiliary
selection are limited, the distance between many genes
positioned and their linked molecular markers is too
large to be used for help. And the other is that the
studies of gene mapping and breeding is out of touch,
the purpose of many researchers is only to locate the
target gene, which has some differentiae in breeding
practice (Wang et al., 2009). Therefore, to find the
practical combination is the main aspect of this
research.
It is a sample for combining the conventional breeding
with molecular marker techniques for selecting the
restorer lines in
Japonica
rice in this study. Using the
different marker polymorphism for molecular marker-
assisted selection, although it wasn’t the marker of the
gene itself, the linkage distance is closer, which
presented some persuasive, and the selection effect is
good. In recent years, with the deepening of the
research on different cytoplasmic male sterility type of
CMS line, breeding requirements of whose ancillary
restorer line is getting higher and higher, especially in
the present study, YS-CMS
Japonica
rice restorer
lines has become a key select object, in the course of
the experiment, although the combination of generation
is low, the degree of separation is larger, it does not
affect restorer selection.
In this study, the results showed that YS-type
cytoplasmic male sterile line overcame the defects of
the existing BT-CMS line, which is a new attempt in
Japonica
rice CMS research in the north of China. We
selected supporting restorer line, which can enhance
the heterosis in YS-type cytoplasm
Japonica
hybrid
rice, and it can be applied to production.
3 Material and Methods
3.1 Plants material
We selected the wide compatibility
Japonica
rice
materials Wanlun 422 as maternal parent, and
Indica
rice WA-type restorer lines Shuhui 527, Miyang 42,
Miyang 46 as paternal parent for crossing. They
generated F
2
-F
4
generations respectively.
3.2 Establishment and cultivation of generations
The tested materials were planted in Rice Research
Institute of Liaoning Province experimental field in
2008 and 2009. The seeds were planted on April 13 to
15, transplanted on May 20 to 25 when the seedling
was 1 meters long, each strain was 5 to 10 rows,
spacing at 30 cm×13.3 cm. The field management was
according to conventional method. 10 strains were
planted in each parental material of Wanlun 422,
Shuhui 527, Miyang 42, Miyang 46, and 100 strains
were grown in F
2
generations of Wanlun 422×Shuhui
527, Wanlun 422×Miyang 42, Wanlun 422×Milyang
46, respectively. We detected the restorer genes with
agronomic trait selection of single plant by using
molecular marker-assisted. F
3
generation was grown
continually in winter of 2008 in Hainan, 4 lines of
each combination, 50 strains in each line. We chose
10 strains from each line to do the testcrossing with
the breeding 8 generation and the stable
Japonica
rice
YS-CMS line, respectively, a total of 120 pairs of
combination (Figure 4).
F
1
generations were planted in spring of 2009 in
Shenyang, 20 strains in each combination. When
heading, they were bagged selfing for calculating the
seed-setting rate. At the same time we planted 55
strains of paternal parent (F
4
), and were paratactically
planted with the gametophyte generation. And then
selected11~12 strains the single row (Figure 4) in F
4
generation. According to the calculation, the
homozygous genotype probability in F
4
generation
plant is approximately 1/5. the hang tag for molecular
detection was carried out based on the order, and
elected per plant of selection for agronomic traits.
After the gametophyte generation heading, we
adopted the pollen staining with 10 lines in each
combination, each line with 3 visual fields, 150~200
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