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Triticeae Genomics and Genetics 2013, Vol.4, No.2, 3
-
11
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6
For the three target characters, the complete
six-parameter model (m, a, d, aa, ad and dd) was first
tested (Table 3). Additionally, for crosses in which the
episthatic effects were non-significant, the reduced
three-parameter model (m, a and d) was used. For the
character GY P
-1
, at least one type of epistasis (a x a, a
x d or d x d) was detected in the five evaluated crosses,
being the episthatic effect (a x a) present in all crosses.
Only CR5 and CR3 presented all three interaction
effects significant for this character. For the character
NP P
-1
, in CR3 and CR5 episthatic interactions were
not detected, therefore only the reduced model is
presented. Thus, the additive component was signifi-
cant for both crosses, but dominance effects were
detected only for CR3. In CR1, CR2 and CR4 at least
one type of epistasis was detected, being the a x a
effect significant in all three crosses. For the character
PP, only in CR1 significant interactions were detected
by the six-parameter analysis. Despite the non-orthog-
onal decomposition, the measure denoted by R
2
allows the idea of the contribution of a particular
genetic effect on the available variability for the target
character (Table 3). Thus, besides the effect of the
mean, the most important genetic effect contributing
GY P
-1
was additive, with 47.79%, 29.92% and
31.21% for CR1, CR3 and CR4, respectively, while
the interactions caused by dominance were of reduced
magnitude among the single effects.
Table 3 Genetic parameter estimates for the simple (additive-dominant) and complete (additive-dominant-epistatic) models and
Relative contribution of parameters (“m”, “a”, “d”, “aa”, “ad” and “dd”) for the simple and complete models , adjusted based on the
mean of evaluated characters, in six generations (P1, P2, F1, F2, RC1F1 and RC2F2) obtained from five oat crosses (CR).
Grain yield per plant (GY P
-1
)
Parameters
(1)
CR1
(6)
CR2
(6)
CR3
(6)
CR4
(6)
CR5
(6)
m
4.34
ns
-12.60**
1.98
ns
7.08**
22.96**
a
2.50**
1.25*
1.94**
-1.21**
-0.30
ns
d
36.56**
83.42**
39.22**
14.25*
-32.34**
aa
9.58**
27.54**
12.63**
5.26*
-11.73**
ad
-2.30
ns
-2.13
ns
8.90*
-2.63
ns
-6.46*
dd
-10.12
ns
-48.56**
-24.28**
-7.78
ns
22.59**
m/a. d. aa. ad. dd
3.14
6.37
0.45
26.57
50.51
a/m. d. aa. ad. dd
47.79
4.21
29.92
31.21
0.73
d/m. a. aa. ad. dd
27.65
32.66
21.65
13.97
13.73
aa/m. a. d. ad. dd
15.65
30.88
18.46
15.04
13.36
ad/m. a. d. aa. dd
1.02
0.2
10.51
4.55
5.79
dd/m. a. d. aa. ad
4.72
25.65
18.99
8.63
15.86
Number of panicles per plant (NP P
-1
)
Parameters
CR1
(6)
CR2
(6)
CR3
(3)
CR4
(6)
CR5
(3)
m
-0.33
ns
-2.01
ns
8.60**
3.77*
5.37**
a
2.42**
0.02
ns
1.77**
-2.15**
-0.66**
d
22.77**
27.91**
-2.78*
3.93
ns
-0.43
ns
aa
8.69**
12.91**
-
4.27*
-
ad
-0.28
ns
-4.15
ns
-
1.33
ns
-
dd
-13.67*
-17.47**
-
-1.60
ns
-
m/a. d. aa. ad. dd
0.02
1.19
93.87
5.82
98.41
a/m. d. aa. ad. dd
64.07
0.01
3.68
84.89
1.4
d/m. a. aa. ad. dd
11.85
25.31
2.43
0.82
0.18
aa/m. a. d. ad. dd
14.31
45.87
-
7.61
-
ad/m. a. d. aa. dd
0.01
5.16
-
0.93
-
dd/m. a. d. aa. ad
9.71
22.54
-
0.31
-
Panicle weight per plant (PP)
Parameters
CR1
(6)
CR2
(3)
CR3
(3)
CR4
(3)
CR5
(3)
m
6.33**
3.26**
3.53**
4.26**
3.91**
a
-0.56**
0.13
ns
-0.29
ns
1.19**
0.61*
d
-3.88
ns
2.05**
1.51*
1.62**
1.82**
aa
-2.46*
-
-
-
-
ad
1.06
ns
-
-
-
-
dd
4.61*
-
-
-
-
m/a. d. aa. ad. dd
47.12
90.06
94.97
90.17
91.63
a/m. d. aa. ad. dd
34.99
0.14
0.61
6.72
2.12
d/m. a. aa. ad. dd
2.2
9.79
4.41
3.1
6.23
aa/m. a. d. ad. dd
7.19
-
-
-
-
ad/m. a. d. aa. dd
1.61
-
-
-
-
dd/m. a. d. aa. ad
6.88
-
-
-
-
Note:
(1)
m: means of homzygous lines derived from F
2
; a: additive gene effect; d: mean of deviations due to dominance; aa: additive
x additive interactions; ad: additive x dominant interactions; dd: dominant x dominant interactions;
ns
Non-significant; * and **
Significant at (p<0,05) and (p<0,01) probability, respectively;
(3)
Additive-dominant model;
6)
Additive-dominant complete model; CR1
(UPF 16/UPF 18); CR2 (UPF 16/UFRGS 7); CR3 (UPF 16/URPEL 15); CR4 (UPF 18/UFRGS 7) and CR5 (UPF 18/UFRGS 17)