Basic HTML Version
Rice Genomics and Genetics 2012, Vol.3, No.1, 1
-
7
http://rgg.sophiapublisher.com
5
Table 2 Single sample mean value examination on phenotype data mean of subgroup
Subgroup
df
The Head Days
Plant Height (cm)
Tillers
Spikelet per Panicle
Brown TKW (g)
(x±s)
(x±s)
(x±s)
(x±s)
(x±s)
Ⅰ
8 94.11±9.87
133.33±33.82
8.44±2.70
237.00±74.79
*
21.15±3.68
Ⅱ
17 93.06±6.64
118.72±24.85
*
8.39±3.60
333.06±109.97
20.77±3.83
Ⅲ
44 92.78±14.27
133.00±23.37
9.58±3.55
270.22±101.1
*
20.46±4.38
Ⅳ
44 92.71±19.75
133.16±26.83
7.87±2.83
316.93±96.54
20.79±3.91
Ⅴ
18 93.50±23.59
140.44±15.77
8.17±3.40
328.61±145.81
20.03±3.26
Ⅵ
17 98.53±14.28
*
136.82±28.80
9.00±2.72
326.53±112.61
21.39±2.65
Overall average
151 93.60±15.94
132.68±25.36
8.63±3.23
302.74±107.83
20.69±3.80
Note: *: Significant at 0.05 probability level
representative of the entire rice germplasm has been
reported (Yan et al., 2007). In the present study, a
subset of the Core Collection, 171 accessions comprising
a rice mini-core collection, suggested genetic diversity
among the rice materials.
OsSPL
primers were designed
according to 19
OsSPL
gene fragment sequences to
surely amplify corresponding
OsSPL
target genes, and
the PCR results indicated that the sequences showed
higher rates of polymorphism, with the exception of
primers SPL 15 and SPL 19. Xie et al (2006) reported
that the
OsSPL
gene expression analysis using real-
time RT-qPCR indicated that the
OsSPL1
-
OsSPL18
genes were classified into three groups. The first
group was highly expressed in the spike, the second
group was expressed in all organs and highly
expressed
in the leaf, leaf sheath and panicle, and the third
demonstrated no differential expression in different
organs. And it has been reported that 11 of the
OsSPL
genes were regulated by miRNA 156. In the present
study, we found little variation in the amplification of
the
OsSPL
genes with expressing uniformly in all
organs and/or little regulation by miRNA 156, and
thus, suggesting little variation in evolutionary
processes between the accessions.
Based on the results of the PCR amplification using
the
OsSPL
primers, the 171 accessions were classified
into two groups and six subgroups. Furthermore, the
accessions of each subgroup showed a similar eco-
geographical distribution, which suggested that their
distribution had some connection with long-term
human selection and ecological adaptation for cultivation.
We found no difference between the Asian and African
cultivars. When comparing the
Keng
(
Japonica
)
Nipponbare
OsSPL
genes and
Hsien
(
Indica
) 9311
OsSPL
genes, there were single base mutations or
cantlet-base deletions in the DNA sequence, though
no differences in the protein sequence, which might
be due to the
OsSPL
genes being indispensable
transcription factors for rice growth and development.
Their functions have been reported only to be
regulated post-transcriptionally (Xie et al., 2006; Dai
et al., 2010). We did not determine whether the similar
eco-geographical distribution had any connection with
the differentiation of
Hsien
(
Indica
) and
Keng
(
Japonica
)
rice because we did not obtain detailed classification
information on the Asian cultivars. Further studies are
required to address this issue.
2.2 Gene-trait association
According to the Hardy-Weinberg equilibrium theory,
the
OsSPL
genes were associated with the traits of
spikelets per panicle, plant height, and days to heading;
these results were obtained by testing the mean of
each subgroup using a single sample mean test and
were essentially consistent with previous studies (Miura
et al., 2010; Jiao et al., 2010). In this study, it was not
found that the
OsSPL
genes controlled tillering and
the brown 1 000
-
grain weight. We speculate that the
major cause of inconsistency might be that tillering is
easily influenced by the environment, whereas the
brown 1 000
-
grain weight is less affected by the
environment. Thus, further research is required to
investigate the role of the
OsSPL
genes in controlling
the brown 1 000
-
grain weight.
3 Materials and Methods
3.1 Test materials and data acquisition
Rice materials used in this study were provided by our
collaborator from Dale Bumpers National Rice Research