Agriculture Reference
In-Depth Information
Step 4: Path Coefficients Analysis
Using the above correlation matrices, path
coefficients at the genotypic, phenotypic, and
environmental levels can be worked out as per
the method described in Chap.
10
. We present
below the tables for the direct and indirect effects
of path coefficient analyses at the genotypic,
phenotypic, and environmental levels (details
are provided in chapter path analysis):
Phenotypic level
:
Y; Xð Þ
phen
VðYÞ
phen
VXð
phen
Cov
q
r
yx
1
¼
78
916
2115
:
p
¼
:
09
18608
:
19
¼
0
:
512
;
Environmental level
:
Cov
ð
Y; X
1
Þ
env
Direct and indirect effects of the yield components on leaf
yield of mulberry
Genotypic path
Shoot length (
p
VðYÞ
env
VXð
env
r
yx
1
¼
75
12
7
:
¼
p
X
1
)
0.323
0.314
0.587
0.080
:
:
14
155
51
Fresh weight of leaf
(
X
2
)
0.068
1.501
1.831
0.360
¼
0
:
178
:
Leaf area
(
0.101
1.462
1.881
0.284
X
3
)
Similarly, other correlation coefficients can
also be worked out as per the above formula
and are presented below:
Leaf weight/m
2
(
0.048
1.012
1
0.534
X
4
)
Residual
¼
0.2048
Phenotypic path
Shoot length (
X
1
)
Genotypic correlation
Y
0.330
0.241
0.492
0.068
X
X
X
X
1
2
3
4
Fresh weight of leaf
(
0.068
1.166
1.537
0.312
Y
1.000
0.516
0.757
0.804
0.474
X
2
)
X
0.516
1.000
0.209
0.312
0.15
Leaf area
(
0.103
1.133
1.581
0.246
1
X
0.757
0.209
1.000
0.973
0.674
X
3
)
2
X
3
0.804
0.312
0.973
1.000
0.532
Leaf weight/ m
2
(
0.049
0.785
0.841
0.463
X
4
0.15
X
4
)
0.474
0.674
0.532
1.000
Residual
¼
0.2293
The direct and indirect effects are the diagonal and off-
diagonal elements, respectively.
Phenotypic correlation
Y
X
1
X
2
X
3
X
4
Y
1.000
0.512
0.751
0.797
0.469
Step 5: Calculation of Genetic Parameters
With the help of the variance-covariance
values of the characters under considerations at
the genotypic and phenotypic levels, we can
work out the genetic parameters like PCV,
GCV, broad sense heritability, and co-
heritability. From the above calculation of
analyses of variance and covariances, we have
the following:
X
0.512
1.000
0.206
0.311
0.148
1
X
2
0.751
0.206
1.000
0.972
0.674
X
0.797
0.311
0.972
1.000
0.532
3
X
0.469
0.148
0.674
0.532
1.000
4
Environmental correlation
Y
X
X
X
X
1
2
3
4
Y
1.000
0.178
0.212
0.284
0.330
X
1
0.429
0.178
1.000
0.099
0.548
X
0.212
0.429
1.000
0.190
0.150
2
X
0.284
0.099
0.190
1.000
0.513
3
A. Variance
components
of
different
X
0.330
0.548
0.150
0.513
1.000
4
characters of mulberry
Leaf weight/m
2
Variance component
Yield/plant
Shoot length
Fresh weight of leaf
Leaf area
g
903.95
18452.68
3496.70
635.89
4780.90
Genotypic
σ
p
916.09
18608.19
3504.02
637.18
4784.24
2
Phenotypic
σ
