Basic HTML Version
Genomics and Applied Biology, 2011, Vol.2 No.6
http://gab.sophiapublisher.com
- 39 -
study, the seven near-isogenic lines of T78 genetic
background had only 86.78% of average genetic
similarity, it is obvious far behind the theoretical value,
which would be possible that the T78 had being varied
in the selfing process. It is from the side to explain
that building near-isogenic lines would be difficulty.
Whereas near-isogenic lines of genetic similarity
coefficient in the T84 and ZS9 background were up to
90% or more, especially the most successful to build
near-isogenic lines of ZS9 background. In this study,
using three different genetic background to simultaneous
build NILs of restore gene can effectively avoid the
individual selection error in the process of rapeseed
background substitution, which might guarantee to
obtain better near-isogenic lines, although the
workload has increased much more, In addition,
analysis of the genetic similarity coefficient showed
that NILs from the background of T78 and ZS9 had
high coefficient of genetic similarity, both of them
had low genetic similarity coefficient with that of
T84. Near-isogenic lines of restore gens built
simultaneous in the large differences of genetic
background become a good research resource for
studying the functions of restore gene.
2.4 The prospects on utilization of rapeseed NILs
of restore gene
The process for building NILs of restorer gene is
relatively time-consuming and labor-intensive. Once
the successful building of NILs is done, it has very
important application values for studying restore gene
and interactions between restore gene and sterile
genes. First of all, NILs can be used to fine map the
restore loci and clone the restore gene. Because of its
almost the same genetic background, compared to
other primary mapping populations such as F
2
and
BC1 etc., the mapping process may be relatively less
of the interference. Secondly, using NILs of restorer
gene can further crack the three-line hybrid system.
All along, it is yet to be studied in-depth for influences
of sterile gene of outside of cell nucleus on phenotypes
of hybrids including yield traits, the restoring abilities
to CMS restorers with different backgrounds, mechanism
of influence of genes in outside cell nucleus (such as
mitochondria genes, etc.) on the fertility of three-line
hybrid system and so on. It would be very important
meaning to these issues mentioned above to fully
understand and apply the three-line hybrid system.
The establishment of three NILs in this research will
provide a good material supporting foundation for
further studies of these issues mentioned above. Thirdly,
the validation of restore gene functions. Restoring
gene’s NILs are two kinds of the lines with or without
restore gene in the same genetic backgrounds. It is the
perfect material to validate the functions of restore
gene by using the line without the restoring gene as
targeted line being transferred the restore gene.
Therefore, the restorer gene’s NILs should be the basis
materials for studies, which has good prospects for
future applications.
3 Materials and Methods
3.1 Rapeseed materials and SSR primers
Ning R7, the restorer line of Rapeseed MI CMS
hybrid Ningza No 3, which the cytoplasm is sterile
cytoplasm, and nucleus has homozygous restoring
gene, used as the source of restorer gene.
T78, T84 and ZS9, used as genetic background donors,
are
Brassica napus
germplasms with large differences
from different genetic backgrounds and comprehensive
excellent agronomic traits of Brassica, which could
not restore the fertility of CMS by identification of
restor-maitaining relationship. These materials mentioned
above were provided by Research group of rapeseed
at Institute of industrial crops of Jiangsu Academy of
Agricultural Sciences.
Total of 75 SSR primer pairs were chosen from these
have the high polymorphism among
Brassica napus
varieties, parts of primers kindly provide by Research
group of rapeseed of Huazhong Agricultural University,
others were downloaded from the website of
www.brassica.info. All of primers were synthesized
by Shanghai Yinjun Biotechnology Company.
3.2 Phenotyping and analysis of agronomic traits
Ten individuals with similar plant type were chosen to
measure the agronomic and economic characters prior
to eliminate both ends of individual of the row before
harvest at the stage of rapeseed maturity. Taking the
average as measured values. Comparative analysis of
the trait values between the genetic background and