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Molecular Plant Breeding 2013, Vol.5, No.9, 47
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63
http://mpb.biopublisher.ca
50
stress
conditions
and
0.40
g
ranging
between
of
0.96~1.67
g,
under
none
saline
conditions
(Table
1),
Salinity
caused
a
reduction
of
54.4%
in
the
tolerant
parent
and
56%
among
the
RILs;
even
though
119
of
the
300
RIL
lines
representing
40%
were
less
affected
by
saline
stress
than
the
susceptible
parent
IR29
(Figure
4),
Thirty
RILs
were
less
affected
in
terms
of
shoot
fresh
weight
under
saline
stress
compared
to
the
donor
parent
(Figure
4);
and
,
20
RILs were
less
affected
in
terms
of
fresh
shoot weight
no
effect
up
to
15%
loss
relative
to
the
control,
1.3 Shoot
dry
weight
The
mean
reduction
of
shoot
dry
weight
due
to
salinity
in
the
susceptible
parent
IR29
was
higher
40.29%,
than
the
average
performance
of
F
5
RILs
22.2%,
Table
1,
There was
a wide
range
in
shoot
dry
weight
among
the RILs.
Some RILs
had
higher
shoot
dry
weight
than
the
mean
of
the
trials
under
both
saline
stress
0.88
g,
and
in
the
non-stress
replication
2.6
g),
while
the
shoot
dry
weights
of
Hasawi
was
0.01
g
and
0.12
g,
respectively.
Sixty-six
RILs
had
shoot
dry
weight
higher
than
the
average
of
the
trial
under
saline
stress.
Twenty-one
RILs
were
less
affected
and
had
dry
shoot
weight
ranging
between
none
up
to
15%
relative
to
none
stress
trials
Based
on
ANOVA,
a
highly
significant
=0.0000,
interaction
between
replication
and
SES
score,
plant
height
and
root
length
were
observed
(Table
2),
Besides
significant
interaction
was
also
observed
between
genotypes
and
all
5
parameters
studied
Table 2 Analysis of variance for salt-tolerant associated traits evaluated in 300 F
5
-derived recombinant inbred lines and their parents
IR29 susceptible, and Hawasi tolerant
Sources
Degrees of freedom
SES
z
score Plant height (cm)
Root length (cm) Fresh weight (g) Dry weight (g)
Replication 2
90.639 ***
5259.381 ***
1169.458 ***
3.117
3.548
Genotypes
301
17.528 ***
117.050 ***
41.482 ***
5.811 ***
5.303 ***
Residual
602
7.229
76.369
26.515
2.283
2.080
Total
905
10.839
101.353
34.018
3.458
3.155
Note: *** indicates that source of variation was highly significant
P
<0.001;
z
Standard evaluation system (IRRI, 1996)
1.4 Trait
correlations
Correlations
among
traits
were
evaluated
as
shown
in
Table
3.
Selecting
for
SES
score
resulted
in
a
negative
response
for
all
4
parameters measured
in
the
experiments;
this
are
plant
height
(r=
-
53),
root
length
(r=
-
47)
shoot
fresh weight
(r=
-
58)
and
shoot
dry
weight
(r=
-
23).
There
was
strong
negative
response
between
shoot
fresh
weight
and
percent
reduction
in
shoot
fresh
weight
under
saline
stress
relative
to
non-saline
conditions
(r=
-
67),
while
a
strong
positive
correlation was
found
between
plant
heights
and
shoots
fresh
weight
(r=49)
and
root
length
and
shoots
fresh
weight
(r=40).
The
highest
(and
negative)
correlation was
found
between
shoot
dry
weight
and
percent
reduction
in
shoot
dry
weight
under
saline
stress
relative
to
non-saline
conditions
(r=
-
77).
However
correlation
between
shoot
dry
weight
and
SES
score,
plant
height,
root
length
and
shoot
fresh
weight
were
less
significant
(r=
less
than
25).
Table 3 Pearson’s correlation coefficients among salt
-
tolerant associated traits measured in F
5
–derived recombinant inbred lines from
IR29×Hasawi
Trait
SES
PH
RL
FW
DW
%RED PH %RED RL %RED FW %RED DW
Standard evaluation
system score (SES)
1.00
-
0.53 ***
-
0.47 ***
-
0.58 ***
-
0.23 *** 0.24 *** 0.19 **
0.39 *** 0.27 ***
Plant height (PH)
1.00
0.34 *** 0.49 *** 0.21 *** 0.32 ***
-
0.05
-
0.27 ***
-
0.21***
Root length (RL)
1.00
0.40 *** 0.17 **
-
0.15 **
-
0.42 ***
-
0.23 ***
-
0.14 *
Fresh weight (FW)
1.00
0.23 ***
-
0.21 ***
-
0.17 **
-
0.67 ***
-
0.28 ***
Dry weight (DW)
1.00
-
0.05
-
0.01
-
0.13 *
-
0.77 ***
PH reduction
1.00
0.50 *** 0.32 *** 0.28 ***
RL reduction
1.00
0.28 *** 0.18 **
FW reduction
1.00
0.25 ***
DW reduction
1.00
Note: *, **, *** indicate a significant correlation at
P
<0.05,
P
<0.01 and
P
<0.001, respectively