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Molecular Plant Breeding 2010, Vol.1 No.1
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Page 4 of 10
QTLs are clustered in several chromosomal regions.
The detail information about the location, explained
variation (
R
2
), and additive effect of QTL detected for
yield and yield-related traits are listed in Table 3,
Table 4 and Figure 1. Some yield traits were selected
to be analyzed in detail as follows.
Thousand grain weight (1000
-
GWt)
Ten QTLs were detected for the trait of 1000
-
GWt on
chromosomes 3
、
4
、
5
、
6 and 11, explaining the
phenotypic variance from 3.77% to 28.67% . The loci
of
qGWt
-
6
-
1
and
qGWt
-
6
-
2
for the 1000
-
GWt are
reduced from the parent of Yuexiangzhan, whereas the
other eight loci for the 1000
-
GWt are increased by the
wild rice allele. The loci of
qGWt
-
5
-
1
、
qGWt
-
5
-
2
and
qGWt
-
11
-
1
explained the largest phenotypic variance
(28.67%
、
26.29% and 24.28%, respectively) the
increase of the 1000
-
GWt (2.49 g
、
2.08 g and 5.56 g,
respectively) contributed by the parent of Yuexiangzhan.
Two QTLs,
qGWt
-
4
-
1
and
qGWt
-
11
-
2
,
were detected
in continuing two years.
Grain number per panicle (GN)
Five putative QTLs were found for GN on chromosomes
2
、
10 and 11. These single QTLs explained the phenotypic
variance from 6.07 to 21.51% with LODs ranging from
2.40 to 3.61. The loci for GN,
qGN
-
2
-
1
、
qGN
-
11
-
1
and
qGN
-
11
-
2
, were increased by wild rice alleles with the
numer of 22.72
、
18.77 and 18.81, respectively.
Grain number per plant (GNP)
Three putative QTLs were detected on chromosomes
1 and 2. Alleles from wild rice at all three QTLs
(
qGNP
-
1
-
1
、
qGNP
-
2
-
1
and
qGNP
-
2
-
2)
increased
the number of GNP. The most significant loci for with
the trait of GNP were
qGNP
-
2
-
2
, which explained
33.44% of the phenotypic variance.
Spikelet number per panicle (SN)
Six putative QTLs for SN were mapped on chromosome
2
、
4
、
6
、
7
、
10 and 11. These single QTLs explained the
phenotypic variance from 3.74% to 31.01%. Two loci
(
qSN
-
6
-
1
and
qSN
-
7
-
1
) caused a decrease in SN,
whereas the locus of
qSN
-
7
-
1
was
detected in
continuing two years.
Spikelet number per plant (SNP)
Two putative QTLs (
qSNP
-
2
-
1
and
qSNP
-
2
-
1
) were
identified for SNP on chromosome 2, explaining
16.67% and 31.15% phenotypic variance. Alleles from
wild rice at these loci increased the number of SNP
(819.87 and 1073.85).
Seed set percentage (SSP)
Three putative QTLs for SSP were found on
chromosomes 10
、
11 and 12 that can explain 4.76% and
28.81% phenotypic variance. All of three loci negative
effected on SSP from the wild rice allele. The locus,
qSSP
-
10
-
1
, was detected in continuing two years.
Productive panicle number (PPN)
The loci for PPN was mapped on chromosomes 1
、
2
、
3
and 7. Alleles from wild rice at four QTLs (
qPPN
-
1
-
1
,
qPPN
-
2
-
1
,
qPPN
-
3
-
1
,
qPPN
-
7
-
1
) increased the
number of PPN. The most significant QTL associated
with PPN was the allele,
qPPN-3-1
, which explained
40.51% phenotypic variance. The locus,
qPPN
-
7
-
1
, was
detected in continuing two years.
Spikelet density (SD)
Four QTLs associated with SD mapped on chromosomes
4
、
5
、
6 and 10, and the explained phenotypic variance
ranged from 3.87% to 22.39%. The allele from wild rice
at
qSD
-
5
-
1
has the negative effect for SD. One of QTLs,
qSD
-
6
-
1
, was detected in continuing two years.
Grain yield per panicle (GY)
Three QTLs were identified for GY on chromosomes
2
、
4 and 10 with
R
2
ranged from 5.49% to 15.65%.
Alleles from wild rice at two QTLs (
qGY
-
4
-
1
and
qGY
-
10
-
1
) increased GY by 0.56 g and 0.38 g.
Grain yield per plant (GYP)
Three putative QTLs were identified for GYP on
chromosomes 1
、
2 and 3, which explained the phenotypic
variance from 3.29 to 24.04%.. The strongest positive
effect was detected at
qGYP
-
3
-
1
for GYP on
chromosome 3, which showed 13.31 of the additive effect.
2 Discussions
Wild rice G52
-
9 is a germplsam of common wild rice
collected from Gaozhou wild rice reserve in Gaozhou
city of Guangdong province in China, where is the
transitional region from southern subtropics to north
subtropics. Gaozhou wild rice reserve is the largest wild
rice population in Guangdong Province covering about