Agriculture Reference
In-Depth Information
carry out suitable experiments to obtain estimates in
more years and sites, but this involves extra time and
effort.
The use of cross prediction techniques in selection
will be discussed in greater detail in Chapter 7.
The variate of interest is pea yield. Regres-
sion of
W
r
against
V
r
resulted in the equation:
W
r
=
×
V
r
−
4.817, with standard error
of the regression slope equal to se
b
= 0.0878. An
analysis of variance of
W
r
+
0.837
V
r
showed significant
differences between arrays while a similar analy-
sis of
W
r
−
V
r
showed no significant differences
between arrays. What can be deduced regarding
the inheritance of pea yield from the information
provided? If you were a plant breeder interested
in developing high yielding dry pea cultivars, on
which two parental lines would you concentrate
your breeding efforts? Briefly explain why.
(3) Below is shown an analysis of variance of plant
yield from a 6
THINK QUESTIONS
(1) Given values for the variance of the mean of the
F
2
, and variance of the F
1
, estimate
h
b
and explain
what this tells us about the genetic determination
of the trait.
V
F
2
=
436.72
6 half diallel (including par-
ents). The analysis of variance is from a Griffing's
Analysis (Model 2). GCA
×
F
1
=
V
111.72
=
general combin-
Given below are the variances of the mean from
two parents (P
1
and P
2
)
ing ability, SCA
=
specific combining ability,
, the F
1
,F
2
, and both
backcross families (B
1
and B
2
)
Error
=
random error obtained by replication,
, estimate
h
n
and
explain what the value means in genetic terms.
=
=
df
degrees of freedom and SS
sum of square.
V
P
1
=
14.1
V
P
2
=
12.2
Source
df
SS
F
1
=
F
2
=
V
13.3
V
40.2
GCA
5
4988
V
B
1
=
35.2
V
B
2
=
34.6
SCA
15
6789
Error
21
5412
(2) List the six assumptions necessary for a straight
forward interpretation of a Hayman and Jinks'
Analysis of diallels.
Below are shown values of array means, within
array variances (
V
r
)
Discuss the results from the analysis given that
the 6 parents were: (1) specifically chosen and
(2) chosen completely at random.
(4) It is desired to determine the narrow-sense her-
itability for flowering date in spring canola
(
B. napus
). Both parents and their offspring from
ten cross combinations were grown in a properly
designed field experiment. At harvest, yield was
recorded for each entry and using these data the
average phenotype of two parents (i.e. [P
1
+
and covariances between array
values and non-recurrent parents (
W
r
)
from a
×
Hayman and Jinks Analysis of a 7
7 complete
diallel in dry pea.
Parent
name
V
r
W
r
Array
mean
2)
was considered to be the
x
independent variable
while the performance of their offspring was con-
sidered as the
y
dependant variable. A regression
analysis is to be carried out by regression of the
offspring (
y
) onto the average parent (
x
). The
following data are derived: SP(
x
,
y
P
2
]
/
'Souper'
34.1
19.3
456
'Dleiyon'
99.9
79.3
305
'Yielder'
21.0
11.2
502
'Shatter'
99.4
68.4
314
'Creamy'
49.6
39.4
372
'SweetP'
59.1
48.8
361
)
=
345.32;
'Limer'
61.8
49.2
393
=
(
)
=
SS(
x
)
321.45. Estimate the
slope of the regression (
b
), test if this slope is
491.41; SS
y
