4.3.1. Analysis of Agronomic Traits
In the present study several quantitative traits were scored on 2 mapping populations. Generally F
2
and BC populations are not used to map quantitative traits. One of the major reasons for not doing so is that the robust trait values of
quantitative characters are not available from single unreplicated plants. However in this study we used 3 clones of the same individual plant which were replicated
in a completely randomized design to estimate the environmental variances. However, this would add another uncontrollable variable- transplanting shock of
split tillers. Means of various traits scored on mapping population, parents, and F
1
are given in Table 7 and 8 while raw data are given in Appendix 10. Frequency
distribution Figures 3 and 4, and analysis of variance, broad sense heritability, coefficient of variation, and p value of Kolmogorov-Smirnov-Lilliefors normality
test are given in Table 9 and 10. Table 7 summarized the twelve traits observed on backcross mapping
population. It included ten agronomic traits and two micronutrient content iron and zinc. The backcross population, IR64 and F
1
plants were included in the experimental set of backcross mapping population. IR75862-206-2-8-3-B-B-B
was accidentally excluded therefore no data are available. Some pictures showing various operations are given in Appendix 9.
Table 8 summarized the eleven traits observed in F
2
mapping population. It included ten agronomic traits and iron content. The experimental set included F
2
population, Joryeongbyeo female parent, IR64 male parent, F
1
and reciprocal F
1
. Plant vigor of F
2
mapping population varied widely where some plants showing good vigor, but many of them having very poor vigor. Sterility problem
was also present in many of the plants causing lack of enough grain samples for iron and zinc analysis.
Broad sense heritability estimates for various traits are summarized in Table 9 for backcross mapping population and in Table 10 for F
2
mapping population. For backcross population heritability values ranged from 57.47
to 83.96 while for F
2
population it ranged from 75.57 to 87.74. All the traits had high heritability indicating strong genetic control. Nevertheless, it was broad sense
31
heritability that includes additive, dominant, and interaction effects. Also the experiment was done on one site and one season, therefore the reliability of
heritability estimates is rather poor. Also in our experiments the trait values are based on 3 clones of a single plant as against trait values based on large replicated
plots. However, these results indicated that genetic variation was present for all the traits scored in our experiments.
Table 7. Mean of Some Agronomic Traits and Micronutrient Contents of Backcross Mapping Population, F
1
, and Parents
No Trait BC
1
F
1
IR64 F
1
1 HD 91.50±3.86
94.93±1.71 89.69±1.24 2 FLL
224.55±24.44 226.83±14.64
243.39±18.04 3 FLW
14.08±1.50 13.02±0.85 15.65±0.59
4 PH 84.88±6.00
83.07±3.1 93.04±2.89
5 PL 227.43±19.15
242.81±79.83 236.52±14.68
6 PW 2.05±0.51
1.95±0.46 1.76±0.19
7 TG 188.79±42.59
160.24±28.17 206.24±29.64
8 SS 0.83±0.08
0.87±0.06 0.57±0.06
9 Wt100 2.42±0.16
2.41±0.08 2.52±0.08
10 Wt 34.88±11.56
29.45±12.43 32.14±8.42
11 Fe 4.83±0.73
3.97±0.48 5.97±0.64
12 Zn 19.94±2.61
18.23±1.24 25.44±0.89
Note : HD=heading datedays, FLL=Flag Leaf Length mm, FLW=Flag Leaf Width mm, PH=Plant Height cm, PL=Panicle length mm, PW=Panicle Weight g, TG=Total
Grain Per Panicle grain, SS=Seed Set, Wt100=Weight of 100 grains g, Wt =Weight of grain per plant g, Fe=iron content of polishded ric grain ppm, Zn=Zinc content of
polished rice grain ppm
Table 8. Mean of Some Agronomic Traits and Micronutrient Content of F
2
Mapping Population, F
1
, and Parents
No Trait F
2
Joryeongbyeo IR64 F
1.1
F
1.2
1 HD 80.04±6.73
71±6.1 87±2.3 71±2.6 72±2.2
2 FLL 213.33±54.95 186±28.9 229.3±35.5
173±21.2 187.8±10.4
3 FLW 10.88±1.98
9.4±0.5 11.6±1.2 10.1±0.6 10.7±0.5
4 PH 60.94±11.23 50.9±12.1 72.9±7.1
58.8±12.6 67.9±5.9
5 PL 187.49±28.44 144.3±12 230±19.5
176.8±12.9 181.5±9.7
6 PW 1.94±1.07
1.3±0.3 3.4±0.7 0.8±0.3 0.8±0.2
7 TG 106.86±63.01 83.2±15.9 172±35.3 100.2±19
110.1±6.8 8 SS
0.45±0.18 0.6±0.1
0.7±0.1 0.1±0.1 0.1±0 9 Wt100
2.33±0.27 2.3±0.2
2.5±0.1 2.4±0.1 2.5±0.1 10 Wt
14.92±15.87 3.9±2.0
41.7±7 8.3±2.54 8±4.8
11 Fe 2.38
±0.77 9.53±1.16 2.10±0.6 nd nd Note: The code of the traits followed the note at Table 7
=based on 44 F
2
plant data, =based on two plants data, nd = no data available.
32
IR64 Hdg
FLW
PL
TG
Fe FLL
PH
PW
SS
Zn Wt
Wt100
F
1
IR64 Hdg
FLW
PL
TG
Fe FLL
PH
PW
SS
Zn Wt
Wt100
F
1
Figure 3. Frequency Distribution of Several Traits in Backcross Population
Note: The code of the traits followed the note at Table 7
FLW HDG
PH FLL
PL PW
TG SS
Wt Wt100
= Joryeongbyeo = IR64
= F
1
FLW HDG
PH FLL
PL PW
TG SS
Wt Wt100
= Joryeongbyeo = IR64
= F
1
Figure 4. Frequency Distribution of Several Traits in F
2
Population
Note: The code of the traits followed the note at Table 7. 33
Table 7 and 8 summarized the value of each generations included in the experiment for backcross and F
2
mapping population, respectively. The value of both populations was not comparable since it came from different cross
combination. Nevertheless, IR64 were used in both cross combination. In general there is a close agreement between various trait scored on IR64 for both
experiments. Nevertheless, most of the plants in backcross experiment were relatively tall compared to the one in F
2
experiment Tables 7 and 8. Similarly differences in grain weight were also recorded.
Table 9. Summary of Analysis of Variance Component, Heritability, and Normality Test for Backcross Mapping Population
No Trait MS
MSE F
P σ
2 g
σ
2 p
H
2
CV P of
normality 1 HD
45.67 8.21
5.57 0.001 42.94 51.14
83.96 3.13 0.04
2 FLL 2517.73
1239.06 2.03
0.001 2104.72 3343.77 62.94 15.58 0.81 3 FLW
6.73 2.10
3.20 0.001 6.03 8.13
74.12 10.30
0.73 4 PH
107.97 62.92
1.72 0.001 87.00
149.92 58.03
9.35 0.35 5 PL
1144.17 436.26
2.62 0.001 998.75
1435.01 69.60
9.18 0.63 6 PW
7048.81 2638.82
2.67 0.001 6169.21 8808.03 70.04 25.06 0.34
7 TG 5249.10
2331.87 2.25
0.001 4471.81 6803.68 65.73 25.57 0.52 8 SS
0.02 0.01
3.78 0.001 0.02 0.02
77.53 8.81
0.00 9
Wt100 0.07 0.01 5.48
0.001 0.07 0.08 83.44
4.65 0.01
10 Wt 387.51
167.51 2.31
0.001 331.67 499.19 66.44
37.11 0.34 11 Fe
1.52 0.90
1.68 0.001 1.22 2.13
57.47 19.28
0.85 12 Zn
19.56 5.49
3.56 0.001 17.73 23.22
76.35 10.82
0.00
Note: The code of the traits followed the note at Table 7. MS=mean square of treatment, MSE=mean square of error, F=F value, P=probability
value, σ
2 g
=genetic variance, σ
2 p
=phenotypic variance, CV=coefficient of variance, P of normality=P value of Kolmogorov-Smirnov-Lilliefors test.
Table 10. Summary of Analysis of Variance Component, Heritability, and Normality Test for F
2
Mapping Population
No Trait MS
MSE F P
σ
2 g
σ
2 p
H
2
CV P of
normality 1
HD 106.53 15.97
6.67 0.001 101.20 117.17
86.37 4.99 0.00 2 FLL
7981.76 1065.19 7.49 0.001 7626.70 8691.89 87.74 15.30 0.02
3 FLW
10.96 1.47 7.47
0.001 10.47 11.94 87.71
11.13 0.24
4 PH
345.28 51.38 6.72
0.001 328.15 379.53 86.46
11.76 0.25 5 PL
2192.83 416.74 5.26 0.001 2053.92 2470.66 83.13 10.89 0.65
6 PW
3.13 0.78
4.02 0.001 2.87 3.65
78.65 45.50
0.00 7 TG
8240.47 2404.50 3.43 0.001 7438.97 9843.46 75.57 45.89 0.04
8 SS
0.07 0.02
4.07 0.001 0.06 0.08
78.90 29.02
0.12 9
WT100 0.16 0.03
6.32 0.001 0.15 0.18
85.69 6.90
0.76 10
WT 741.25
137.35 5.40
0.001 695.47 832.82 83.51
78.55 0.00
Note: The code of the traits followed the note at Table 7. The code of header followed Table 9.
34
Test of the normality of frequency distribution Table 9 for backcross mapping population and Table 10 for F
2
mapping population. For backcross mapping population, flag leaf length, flag leaf width, panicle length, total grain
number per panicle, and iron content of polished rice grain had normal distribution. While heading date, seed set, weight of 100 grains, and zinc content
of polished rice grain were not normally distributed p value of 0.04, 0.00, 0.01, and 0.00 respectively.
However for F
2
mapping population, most of the traits had very low p value from 0.00 to 0.25 indicating that those traits were not normally distributed.
There may be several reasons for this. For example, high sterility, that is normally present in progenies of crosses involving indica and japonica parents.
The sterility may be caused by the sterility genes that cause distorted segregation Septiningsih et al. 2003 in the progeny.
Based on the population characteristics summarized in Tables 7 and 8 and the frequency distribution illustrated in Figure 3 and 4, it seem that the traits were
quantitatively controlled. Transgressive segregation was observed for most traits indicating that genes controlling these traits are in dispersion phase.
Due to sterility problem, less vigor of the japonica variety in tropical conditions, and the occurrence of tungro disease individuals in F
2
mapping population were not very productive. Most of the productive plants having enough
grain samples had the characteristic closely resembled with IR64. It might due to the sterility and incompatibility those occurred between IR64 and Joryeongbyeo.
For the above reasons QTLs for iron content in F
2
mapping populations were not mapped.
Measurement of iron content using colorimetric method is relatively simple. It is a semi quantitative method Choi et al. 2007 and could be used to distinguish
between genotypes having high and low iron content. This method is very useful for breeding material selection those have few amount of grain sample. For
further precise screening, selected genotypes from colorimetric screening are analyzed using Inductively Coupled Plasma ICP method such as has been done
in ASL Laboratory of IRRI Appendix 8.
35
4.3.2. Quantitative Trait Loci for Agronomic Traits
Kategori