1. The Community of Practices “Concept applied to rice production in the Mekong Region: Quick conversion of popular rice varieties with emphasis on drought, salinity and grain quality improvement
Improvement of drought tolerant variety, IR57514 , for grain aroma and cooking quality using marker-assisted selection
Ubon Ratchathani University

2. Background
IR57514 is an elite drought tolerant and high yielding rice variety developed by IRRI which is well adapted to rainfed lowland in Mekong region where the areas are mostly limited by abiotic stresses with unpredictable rainfall patterns.
BUT
it was not successfully adopted by farmers due to unsatisfied of grain qualities. IR
aroma +
good cooking quality
SOLUTION
Problem ?
Breeding IR57514 for grain aroma and good cooking quality traits will greatly enhance both quality and productivity of rice in the rainfed lowland areas in Mekong region.

3. Objective
The research was aimed to improve grain aroma and cooking quality of IR Marker-assisted selection (MAS) in backcross breeding will be used to transfer favorable alleles of genes / QTL of grain aroma and good cooking qualities traits from KDML105 into genetic background of IR57514.

4. Plant materials
The marker-assisted backcross breeding was conducted using IR57514 as the recipient parent.
KD571-77, the backcross introgression line of KDML105 carrying Xa21 for bacterial leaf blight resistance and Sub1A, Sub1B and Sub1C for submergence tolerance, was used as a donor parent for grain aroma and good cooking quality traits.
The backcross procedure for introgression of the target QTLs was conducted at Ubon Rice Research Center and Kasetsart University, Kamphangsean Campus, Nakorn Pathom.

5. MAS Phase I
Breeding scheme:
MAS Phase II

6. waxy for amylose content & gel consistency,
1st workshop (May 21 – 30, 2007)
352 BC3F1 were produced from the crosses between the selected 14 BC2F1 and IR57514.
14 BC3F1 were selected based on MAS:
BADH for grain aroma,
waxy for amylose content & gel consistency,
SNP 2341 for gelatinization temperature
PB7-8 for Xa21 bacterial leaf blight resistance
Phase I
MAS Phase II

7. 1640 BC3F2 plants were generated from 11 BC3F1
2nd workshop
2nd workshop (Nov 10 – 24, 2007)
1640 BC3F2 plants were generated from 11 BC3F1
The 436 BC3F2 progeny were selected from 1640 BC3F2 based on phenotype.
33 lines were selected using MAS:
BADH for grain aroma,
waxy for amylose content & gel consistency,
SNP 2341 for gelatinization temperature
PB7-8 for Xa21 bacterial leaf blight resistance characters.
MAS Phase II

8. 3rd workshop (May 1 – 15, 2008)
These 33 families of BC3F2 were selfing to generate 2,595 lines of BC3F3 progeny.
Marker-assisted selection (MAS):
BADH for aroma
waxy for amylose content and gel consistency
SNP2341 for gelatinization temperature and
PB 7-8 for Xa21 bacterial left blight resistance
370 BC3F3 progeny were selected based on genotype (260 lines) and based on phenotype (110 lines).
The selected 370 BC3F3 progeny will be evaluated for the traits of interest comparing to the recipient variety, IR
3rd workshop
MAS Phase II

9. Grain quality: aroma, cooking quality BC3F2 BC3F5
MAS Phase II
4th workshop (May 1 – 15, 2008)
Traits Validation
Grain quality: aroma, cooking quality
BC3F2
BC3F5
Submergence tolerance
BC3F4
Drought tolerance

10. Traits Validation : Grain aroma and cooking quality in BC3F2 and BC3F5
Grain Quality
Grain aroma : sensory test
Amylose content : colorimetric method described by Julaino (1987)
Gel consistency : described by Tan et al. (1999)
Gelatinization temperature : Alkaline test (alkali spreading value ) as described by Little et al. (1958)

11. Traits Validation : Submergence tolerance (BC3F4 and BC3F5)
IR57514
KDML105
FR13A
RD6
Data recording ;
Percent of plant survival (PPS)
Percent of plant elongation (PPE)
Leaf senescence
(Siangliw et al., 2003).
Location : Kasetsart University,
kampangsean campus,
Nakorn Pathom
Results
370 BC3F4
173 BC3F4
PPS
PPS, LS, PPE
56 BC3F5
20 BC3F5

12. Submergence tolerance validation in 56 BC3F5 lines.

13. Validation : Drought tolerance (BC3F4)
Experiment Design : Randomized Complete Block Design in CPA
Augmented Design in RGDU
Check varieties: IR  Tolerance check
KDML105, KD  Susceptible check
Population size: BC3F4 lines  Chumpae Rice Research Center
173 BC3F4 lines  Kasetsart University, Kampangsean campus
Data recording
 GY (Grain yield)  PH (Plant height)
 PN (Panicle number)  TN (Tiller number)
 FWD (Flowering date)

14. Grain quality genotyping and validation
Final Lines
Grain aroma and cooking quality testing (BC3F5 progeny)
Grain quality genotyping and validation
No. #
Aroma GT AC GC
Lines
BADH
Score
SNP2341
Waxy
KD571-77 1 KD 5 16 73
IR57514 3 IR 2 33
102
BC3F5 #
KD*
4.9 19 86
BC3F5 #
5.0 82
BC3F5 #
109 4
BC3F5 # 20
106
BC3F5 # 17
108 6
BC3F5 #
146 7
BC3F5 # 22
104 8
BC3F5 #
123 9
BC3F5 # 21
131 10
BC3F5 #

15. Submergence validation (BC3F5) Drought validation (BC3F4)
Final Lines
Submergence tolerance and drought tolerance validation
No.
Lines
Submergence validation (BC3F5)
Drought validation (BC3F4)
Grain yield (kg rai-1)
Sterility (%)
Flowering date
PPS
PPE LS
Irrigated
Drained
KD571-77
67.98
33.81
20.14
87.68
90.46
3.61
7.18 90 88
IR57514
73.39
27.21
31.99
140.82
121.40
4.37
4.93
103 98 1
BC3F5 #
79.29
24.93
33.04
101.40
103.47
1.92
0.67 80 81 2
BC3F5 #
73.61
21.50
27.81 - 3
BC3F5 #
81.35
25.96
30.81
125.89
93.61
1.11
2.39 83 92 4
BC3F5 #
74.48
24.89
32.05
94.05
89.64
1.85
6.95 5
BC3F5 #
75.99
16.45
31.98
95.90
102.62
0.93
1.43 84 6
BC3F5 #
69.37
25.53
33.50
119.60
100.76
2.04
1.86 91 7
BC3F5 #
73.29
35.57
32.04
125.83
96.38
2.02
4.65 89 8
BC3F5 #
71.82
22.84
28.08
137.80
110.51
4.29
11.23
101
100 9
BC3F5 #
74.89
22.49
32.78
139.04
95.27
5.64
13.76
104
102 10
BC3F5 #
78.15
24.97
28.34
120.49
93.91
9.77
14.89
Mean
72.86
26.90
29.46
118.63
103.69
2.55
4.17
88.14
90.02
Prob. **
LSD0.05
2.36
1.67
0.63
1.68
1.48
0.17
0.30
0.68
0.64

16. Conclusion
We aimed to improve grain aroma and cooking quality of IR57514 using MAS.
10 selected BC3F5 were finally selected for grain aroma and cooking quality traits based on genotype (MAS) and these lines were validated for grain quality, submergence tolerance and drought tolerance.
These selected lines will be on trial both in station and on farm in rice production areas in Mekong region.
Marker assisted selection (MAS) technology was an excellent tool for rice breeding program.
MAS technology jointly with classical breeding will increase the effectiveness and precision of selection process.
MAS will be shortening the breeding program and also reduce the cost of breeding program.
Breeding IR57514 for grain aroma and good cooking quality traits will greatly enhance both quality and productivity of rice in the rainfed lowland areas in Mekong region.

17. Acknowledgments Rice Gene Discovery Unit (RGDU)
National Center for Genetic Engineering and Biotechnology (BIOTEC)
Generation Challenge Programe (GCP)