variance E. The variance component can be used to estimate variance of population through Singh and Chaudhary formula 1979 as follows: E
=
� � +� � +�
; = 4�
− � � − � � ; = 4� � + 4� � −
4� − ; ℎ
��
=
� ��
=
�+
+ �+
; ℎ
��
=
�� ��
=
�
+ �+
B
1
, B
2
= BCP1, BCP2; VG = variance of genetic; VP = variance of phenotype; VA = variance of additive; h
2 bs
= broad sense heritability; h
2 ns
= narrow sense heritability. Heritability is high if h
2
0.50, medium if 0.2 ≥ h
2
≥ 0.50, and low if h
2
0.2 Halloran et al. 1979. All statistical analyses were performed with SAS version 9 software. The
SAS listing program for scaling test and joint scaling test analysis were developed by Gusti N Adhi-Wibawa Unpublished, listed in Appendix 3.
4.2.3.2 Estimation of gene action in F2 population
Gene action in F2 population was estimated based on skewness and kurtosis curve Roy 2000. The traits analyzed were number of filled and unfilled grain.
When the skewness value = 0, gene action is additive; when the skewness 0, gene action is additive with duplicate epistasis; meanwhile when the skewness 0, gene
action is additive with complementary epistasis. When the kurtosis value = 3, graphic of distribution is mesokurtic; when the kurtosis 3, the graphic of
distribution is platykurtic, it means trait is controlled by polygenic. When the kurtosis 3, graphic of distribution is leptokurtic, it means trait is controlled by one
or two genes. Continues distribution means that trait is controlled by quantitative gene ad polygenic. Skewness value is calculated using equation
�� � =
∑
�
− ̅
� �=
�− �
, while kurtosis value is calculated using equation � � =
∑
�
− ̅
� �=
�− �
where Yi = value of genotype i, s = standard deviation, N = number of data. All statistical analyses were performed with Minitab 14 software.
4.3 Result and Discussion 4.3.1 Generation mean and gene action under stagnant flooding stress
Plant height and length of panicle of IR 42 P1 were not significantly different with IRRI 119 P2. While plant height and grain yield of F1 were greater
than mean of both of parents. Progeny with higher phenotypic compared to both of parents indicating the gene action that is over dominant. Over dominant allele
means that the allele brings one copy which having greater effect than two copies Peterson 1991. However, model of additive were unable to identify some of QTls
gene action, whether they are dominant, or over dominant gene action. Meanwhile, mean of backcross population to superior parent BCP2 showed higher values on
plant height and weight of 100 grain. Plant height, flowering time, and 100 grain weight of BCP1 and BCP2 were between both of two parents. Grain yield of BCP1
and BCP2 was higher than superior parent Table 4.1.
Table 4.1 Mean and standard error of rice population P1, P2, F1, F2, BCP1, and BCP2 of IR 42 x IRRI 119 crossing under stagnant flooding stress
Generation Plant
height cm
No. of tiller
Flowering time
DAS Length of
panicle cm
100 grain weight g
Grain yield g
P1 143 ±
2.04 7 ±
0.69 107 ± 0.87
25.2 ± 0.29
2.34 ± 0.07
7.33 ± 0.51 P2
145 ± 1.81
5 ± 0.21
96 ± 1.57 25.5 ±
0.48 2.78 ±
0.08 9.31 ± 0.73
F1 150 ±
1.17 8 ±
0.52 103 ± 0.47
25.0 ± 0.59
2.63 ± 0.02
15.61 ± 0.81
F2 141 ±
0.56 10 ±
0.22 104 ± 0.34
26.9 ± 0.07
2.59 ± 0.02
9.61 ± 0.30 BCP1
142 ± 1.49
9 ± 0.65
105 ± 0.78 26.7 ±
0.21 2.37 ±
0.03 11.13 ±
0.90 BCP2
143 ± 1.28
6 ± 0.51
102 ± 1.16 26.6 ±
0.13 2.67 ±
0.05 11.35 ±
0.94
Abbreviation: DAS = day after sowing
F
2
population had a frequency distribution which were exceeded the highest parent Fig. 4.1. This indicates there was segregrant transgressive, where the
additive gene affected greatly more than other gene actions. In the BCP1 and BCP2 generation, positive alleles of additive gene on plant height, panicle length and grain
weight per plant were shown by the average value that is higher than the two parents. Crossing two parents which have similar phenotypes have the possibility
to produce progeny superior to both parents, and it is called transgression Simmonds 1979.
