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Wei et al. (2000) found that there were 35 different gliadin patterns
among 89 Sichuan wheat landraces, while only 18 landraces had unique
gliadin patterns. In this study, 36 out of 40 (90%) Sichuan modern
wheat cultivars had unique gliadin patterns. In comparison with
Sichuan wheat landraces, larger gliadin variability was present in
Sichuan modern wheat cultivars.
Sozinov et al. (1987) had identified a block of gliadin bands
(Gld1B3) as a marker for the presence of 1RS chromosome
segment from rye in wheat. Using Gld1B3 as marker, it was
found that nine cultivars (22.5%) (Chuanmai 19, Chuanmai 21,
Chuannongmai 1, Miannong 3, Miannong 4, Mianyang 21, Shuwan 761,
Yiyuan 2 and Yumai 4) carried the 1RS chromosome segment.
RAPD polymorphisms: Fifty-five 10-mer arbitrary primers were used for
PCR amplification of the genomic DNA of 40 Sichuan wheat cultivars,
among which PCR products of 32 primers (58.2%) showed polymorphism. A
total of 183 bands were amplified using 55 primers in the 40
cultivars. Ninety-three out of 183 bands (50.8%) were polymorphic,
among which 1 to 11 polymorphic bands were amplified by each primer,
with 1.7 polymorphic bands per primer on an average. The similar
results were reported in other wheat genotypes by He et al. (1992)
and Sun et al. (1998).
All the 183 bands were used to calculate genetic similarity (GS)
among 40 Sichuan wheat cultivars. The GS value ranged from 0.804 to
0.991, with the mean of 0.887. The highest genetic similarity was
found between Yaanzao and Datouhuang, while the lowest genetic
similarity was observed between Shannong 205 and Yiyuan 2.
RAPD makers allows the rapid, efficient resolution of high levels of
polymorphism among closely related lines of common wheat (He et al.
1992; Sun. et al. 1998). The genetic diversities (GD) among 40
Sichuan wheat cultivars were obtained from 1-GS matrix. The genetic
relationships among 40 Sichuan wheat cultivars were analyzed by a
UPGMA method (Fig. 3). The results showed
that all 40 cultivars could be distinguished by RAPD markers,
including closely related sister lines (such as Fan 6 and Fan 7). It
was similar to the results reported by He et al. (1992) and Sun et
al. (1998). Three cultivars (i.e. Shannong 205, Yiyuan 2 and
Chengdu-guangtou) were less related with other cultivars, and
divergent from the other cultivars. Two subgroups were evident for
the remaining 37 cultivars, with the first subgroup including 24
cultivars. The cultivars were more closely related with others among
the first subgroup, while more diverse among the second subgroup.
Three cultivars introduced from Italy (Abbandanza, Ardito and
Mentana) were distributed within different subgroups because they
were included in the different pedigree of some Sichuan wheat
cultivars (Yu 1998; Yen 1999).
Acknowledgments
The authors are thankful to the Science and Technology Committee,
and Education Committee of Sichuan Province, China for their
financial supports.
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