Agriculture Reference
In-Depth Information
Without using regression, estimate the narrow-
sense heritability (
h
n
)
Complete the analysis of variance and explain
your conclusions from the analysis. Given
that the parents were chosen at random,
how would this change the results and your
conclusions?
Plant height was also recorded on the same
diallel families and an additive-dominance model
found to be adequate to explain the genetic vari-
ation in plant height. Array variances
V
r
s and
non-recurrent parent covariances (
W
r
s) were cal-
culated and are shown alongside the general com-
bining ability (GCA) of each of the five parents,
below:
for seed yield, and explain
this value in genetic variance terms. Explain the
analyses for Yield and outline any conclusions that
can be drawn for these data. Explain the analysis
for %Oil (percentage of seed weight that is oil) and
outline any conclusions that can be drawn from
these data. Which
one
of these four genotypes
would you choose as a parent in your breed-
ing programme? Explain your choice. Describe
any difficulties suggested from these analyses in a
breeding programme designed for selecting lines
with high yield and high percentage of oil.
(9) F
1
,F
2
,B
1
and B
2
families were evaluated for
plant yield (kg/plot) from a cross between two
homozygous spring wheat parents. The following
variances from each family were found:
σ
Parent
V
r
W
r
GCA
2
2
F
1
=
σ
F
2
=
123.7;
496.2
−
1
491.4
436.8
0.76
2
2
σ
B
1
=
σ
B
2
=
324.7
Calculate the broad-sense (
h
b
)
357.2;
+
2
610.3
664.2
12.92
and narrow-
−
3
302.4
234.8
14.32
sense (
h
n
)
heritability for plant yield. Given the
heritability estimates you have obtained, would
you recommend selection for yield at the F
3
in a
wheat breeding programme, and why?
(10) Griffing has described four types of diallel cross-
ing designs. Briefly outline the features of each
Method 1, 2, 3 and 4. Why would you choose
Method 3 over Method 1? Why would you choose
Method 2 over Method 1?
A full diallel, including selfs was carried involv-
ing five chickpea parents (
assumed to be chosen
as fixed parents
), and all families resulting were
evaluated at the F
1
stage for seed yield. The
following analysis of variance for general com-
bining ability (GCA), specific combining ability
(SCA) and reciprocal effects (Griffing's Analysis)
was obtained:
4
310.2
226.9
−
15.77
5
832.7
769.4
+
17.93
Without further calculations, what can be
deduced about the inheritance of plant height in
chickpea?
(11) A 4
4 halfdiallel design (with selfs) was carried
out in cherry and the following fruit yields of each
possible F
1
family were observed:
×
Small reds
Small reds
12
Big yields
Big yields
27
36
Jim's delight
Jim's delight
21
35
27
Jacks' best
Source
d.f.
MS
Jack's best
28
27
26
21
GCA
5
30 769
SCA
10
10 934
Reciprocal
10
9638
Error
49
5136
From the above data, determine the narrow-
sense heritability for yield in cherry.
