Page 9 - Molecular Plant Breeding

Wang et al., 2011, Genetic Diversity of the Selected 64 PotatoGermplasms Revealed byAFLPMarker, Molecular Plant Breeding Vol.2 No.4 (doi: 10.5376/mpb.2011.02.0004)
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indicating that the AFLP approach is accurate and
reliable. AFLP markers have been widely used in
analyzing the genetic diversity of germplasms and
genetic relationship because of its rich information,
high polymorphism and stability (Lucchini et al., 2003).
The study of Zhou (1998) showed that when the
number of markers 20 below, the information
obtained is not very reliable, as the number of locus
increases, the amount of information generated and
reliability have increased, and when the number of loci
is reached or exceeded 70, the reliability of the
information provided was stable. In this study, 505
AFLP loci were obtained, its stability and reliability of
the information are sufficient for analyzing the genetic
diversity of potato. In the test, cultivar Qingshu328 is
pre-cultivated name of Qingshu2, processing cultivar
F18 and Shepody are the same species, processing F1
and anti-virus E19 are the same species, in the
dendrogram Qingshu2 and Qingshu328 clustered
together, their GS of 0.91, F18 and Shepody clustered
together, the GS of 0.90, F1 and E19 clustered
together, their GS of 0.89, these results not only
showed the differences between individual of same
species, but dismayed that the AFLP markers is
accurate and reliable; E104 and E107 have highest GS
up to 0.97, indicating E104 and E107 have similar
parents or the source of parents is relative, the two
materials need to be identified because of its maybe
same cultivars drawn from different countries with
different names.
2.2 Genetic Uniqueness of Potato
In breeding, select hybrid parents with genetic
differences for hybridization can obtain high heterosis.
It is partic- ularly important for potato to broaden the
narrow genetic base. The traditional breeding
approach chose the hybrid parents according to
phenotype of plant accompany of many limitations.
The reproduction of potato belongs to vegetative
organs. Tetraploid and highly heterozygous are the
main characteristic. The separation of their offspring
is much more complicated than the diploid plants. The
effect of selection of parent mterials was affected by
the composition of gene loci, genetic inheritance of
traits and the interacttion of environmental conditions,
which results in potato breeding extremely difficult.
According to statistics, probability of breeding a new
variety is 1/200000, probability of breeding a new
significant variety is one millionth. Therefore, it is
most crucial to select excellent parent meterials in
potato breeding.
2.3 Genetic Diversity of Chinese potato
Analysis showed that CIP potato resources and
Chinese potato varieties with lower genetic similarity
and genetic difference. At the GS of 0.82, most of
Chinese cultivars grouped together, showing that
Chinese cultivars have high genetic similarity and
narrow genetic base. This result is consistent with
results researched befor (Di et al., 2006; Xu and Jin,
2008; Duan et al., 2009). Meanwhile, the 64 potato
materials, of which 47 were introduced from the CIP,
these potato resources are collected from all over the
world, such as Peru, Colombia, Mexico, Bolivia,
Germany, India and other countries, the other 17
potato cultivars were from Qinghai, Gansu, Shanxi
provinces, which formed the basis of genetic diversity
of examined potato germplasms to some extent. The
introduction of the potato CIP resources can be fully
used for potato breeding in China.
3 Materials and Method
3.1 Plant Materials
In this study, 64 potato individuals were examined,
among which 47 germplasms are introduced from CIP
with resistance to virus, processing resources and 17
are Chinese cultivars (Table 2).
3.2 DNA Extraction
The genomic DNA of potato was extracted by
optimized CTAB method. The concentration and
quality of extracted DNA were detected by the
spectrophotometer and 1% agarose gel electrophoresis.
The purified DNA (20 ng/ul) was preserved at -20℃.
3.3 AFLP Analysis
AFLP analysis system was the optimized protocol of
Li (2010). Restriction enzyme MseⅠ and EcoRⅠ
were purchased from NEB (New England Biolabs),
Mse Ⅰ and EcoR Ⅰ adaptors and primers were
synthesized by Shanghai Health Engineering
Biological Engineering Technology Services Limited
(Sangon).