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Lecture of Prof. Zhi Kang Li about rice breeding technology.
Citation preview
GSR Breeding Strategy – Exploiting the
Hidden Reservoir of Diversity for
Improving Complex Traits in Rice
Zhi-Kang Li/CAAS
GA biosynthetic pathway
KS
GA15
GA24
GA44
GA19
GA12 -aldehyde
Geranylgeranyl
ent- Copalyl diphosphate
ent -Kaurene
ent -Kaurenol
ent -Kaurenal
ent -Kaurenoic acid
ent -7a-hydroxy
GA12
GA9
GA53
GA20
KO
KAO
GA
GA3ox
GA4 GA1
GA7ox
GA13ox
kaurenoic acid
diphospate
C20ox
AS
CPS
KS
KO
KAO
sd-1
Subjects
� Concept of GSR
� Introduction
� Perspectives
� GSR Breeding Strategy and
Technology
The impact of ‘Green Revolution’ in ChinaYield
Impact of ‘Green Revolution’
30000
40000
50000
60000Impact of hybrid rice
Yield/unit area
Total production
Yield
0
10000
20000
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
Year1988
1990
1992
1994
1996
1998
2000
2002
Important problems in rice
production worldwide
• Increasing problems in abiotic and biotic
stresses
• Over-use of pesticides • Over-use of pesticides
• Abuse of chemical fertilizers
• Shortage of water
• Ever increasing demands for yield increase
• Urgent need for improved quality
Total grain production(( ((in
unit area yield Fertilizer application and grain production in China
4000
4500
70000
75000
Fertilizer use
Current agricultural practices: higher inputs-for high yields- polluted
environments
China consumes ~1/3 of the global production of chemical fertilizers
and pesticides annually on only 7% of the world’s cultivated lands
In China
Fertilizer use (in 10000t)
Total grain production
10000 t
)、
)、
)、
)、unit area yield
(kg/10ha)) ))
0
500
1000
1500
2000
2500
3000
3500
4000
1975 1978 1982 1985 1988 1991 1994 1997 2000
15000
20000
25000
30000
35000
40000
45000
50000
55000
60000
65000Fertilizer use
Grain production
Grain yield per unit area
25
30
35
40
3035404550
6
7
90
110
130
150单产农药化肥
(( ((million ton
)) ))
10000 ton
)) ))
Trends of rice production and uses of pesticides
and fertilizers in China in the last 30 years
ton/ha)) ))
0
5
10
15
20
1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 200551015202530
3
4
5
1978 1981 1984 1987 1990 1993 1996 1999 2002 200510
30
50
70
90
Fertilizers
(( ((
Pesticides
(( ((10000
Yield
(( ((ton/ha
350 350
Grain yield(ton/hm2)
Grain yield/ha
1
2
3
4
5
1961 1966 1971 1976 1981 1986 1991 1996 2001 2006
/
Grain yield per unit area
0
50
100
150
200
250
300
350
1961 1966 1971 1976 1981 1986 1991 1996 2001 2006
氮肥
用量
(公
斤/
公顷
)
0
50
100
150
200
250
300
350
氮肥
生产
效率
(kg/k
g)
氮肥用量
PFP
Nitro
gen
consu
mption(k
g/h
m2)
Nitro
gen
use
effic
iency
(kg/k
g )
N consumption
NUE
1961 1966 1971 1976 1981 1986 1991 1996 2001 2006
350
300
250
200
150
100
50
0
350
300
250
200
150
100
50
0
Annual yield losses
� ~20% from abiotic stress: drought,
problem soils, etc) problem soils, etc)
� ~15% from biotic stress: diseases
and insects, even with the heavy
uses of pesticides.
Water crisis and
drought in China
� Fresh water resources per capita in China is less than a
quarter of the world average;
� Agriculture uses ~70% of the fresh water in China, and
rice uses ~70% of the fresh water used in agriculture;
� Drought is occurring more frequently than ever before;
� Great yield loss of rice to drought in major rice areas.
4.0
5.0
6.0
Yield (t/ha)
Irrigated(40%)
Largely Irrigated
Which places have been left out by Green
Revolution: Rice Yield Gaps in Irrigated and
Rainfed Ecosystems in Asia, 1967-97
80
100
Irrigated Rainfed
0.0
1.0
2.0
3.0
1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997
Year
Yield (t/ha)
Rainfed(30%)
Largely Irrigated
(30%)
Source: M. Hossain, IRRI
0
20
40
60
MC TC
Adoption percentage
of modern cultivars
Consequences of the Green Revolution
ProductivityProductivity
DiversityDiversity
Less inputs, more production, and
environmental sustainability
少投入、多产出、保护环境少投入、多产出、保护环境少投入、多产出、保护环境少投入、多产出、保护环境
Chinese scientists are calling
“Second Green Revolution”
少投入、多产出、保护环境少投入、多产出、保护环境少投入、多产出、保护环境少投入、多产出、保护环境
- to develop and widely adopted “Green Super
Rice” that can produce high and stable yields
under less inputs (chemical fertilizers,
pesticides and water, and stress resilient).
What are “GSR”?
High yielding cultivars with multiple “Green” traits:
Resistances/ tolerances to:
Abiotic stresses: Drought, salinity, alkalinity, etc.Abiotic stresses: Drought, salinity, alkalinity, etc.
Diseases: Blast, bacterial blight, sheath blight,
viruses, and false smut etc
Insects: Brown plant hopper, stem borer, etc
High resource-use efficiencies: Water and nutrients (N, P)
Many target traits:
Yield and its related traits
Stability
To develop GSR rice varieties, breeders
are facing the following challenges:
Stability
- Resistances to biotic stresses
- Tolerances to abiotic stresses
Quality
- Eating, cooking, and milling
- Micronutrients
Where are the sources
of genetic variation
for improving the
‘green’ traits?
Rice Germplasm Collections in
Genebanks Worldwide: ~ 215,000 entries
27% of
modern
10% of 22 wild species
90% of the
Cultivated rice73% of
landraces
varieties
Everson et al. 1998
Status of the International Rice
Genebank Collection at IRRI
AccessionsIncoming
samplesTotal
O. sativa 85,999 15,784 101,783
O. glaberrima 1,333 288 1,621
Wild species 3,970 495 4,465
Total 91,302 16,567 107,869
Characterization of O. sativa
accessions (n=79,925)
Characterization of O. sativa
accessions (n=79,925)
7070
8080
9090
100100
% accessions scored
% accessions scored
00
1010
2020
3030
4040
5050
6060
7070
% accessions scored
% accessions scored
44 morpho-agronomic traits44 morpho-agronomic traits
20,00020,00020,00020,000
30,00030,00030,00030,000
40,00040,00040,00040,000
50,00050,00050,00050,000
Evaluation of rice germplasm for stress
resistance/tolerances at IRRI
Evaluation of rice germplasm for stress
resistance/tolerances at IRRI
Screened Resistant
accessions
accessions
20,00020,00020,00020,000
10,00010,00010,00010,000
Blast
Blast
Bacterial
Bacterial
blight
blight
Sheath
Sheath
blight
blight
Rice tungro
Rice tungro
BPH 1
BPH 1
BPH 2
BPH 2
BPH 3
BPH 3
Green
Green
leafhopper
leafhopper
Whitebacked
Whitebacked
planthopper
planthopper
Cold
Cold
tolerance
tolerance
No.accessions
No.accessions
Cold tolerance (1-3 = tolerant; 5 =
intermediate; 7-9 = susceptible)
Cold tolerance (1-3 = tolerant; 5 =
intermediate; 7-9 = susceptible)
2,000
2,500n=6,625n=6,625
0
500
1,000
1,500
1 3 5 7 9
15
20
25
Yield responses of the 193 parental lines of IRMBN
to the terminal drought under the lowland condition
-19.1±±±±44.0%
0
5
10
15
-100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160
Yield reduction (in %)
Core collections of rice, wheat, corn and
soybean were established with only 5% of
the accessions representing over 90%
genetic diversity of the whole collections. 0.1
Jap. M.
Jap. U.
Jap. L.
Ind. EM.
Ind. M.
Ind. MLJaponica
Indica
0.1
�� Establishment of the core collections for
major crops in the CAAS’s genebank
Comparison of genetic diversity among core collections
with different sampling ratio
Basic Collections Core Collection Mini-core
Accessions Entries sampling % Representation Entries sampling % Representation
Rice 61479 3074 5% 89.9% 300 0.5% 66.6%
Wheat 23135 1160 5% 90.1% 231 1.0% 69.1%
Soybean 28809 1439 5% 91.0% 280 1.0% 71.0%
(Jia jizheng,2004)
Current Status of Characterization and Utilization of
Germplasm Collections in Genebanks Worldwide
- Phenotypic evaluation and description
To identify accessions with desirable (often extreme)
� Collection and conservation largely completed
� Characterization – very superficial
To identify accessions with desirable (often extreme)
phenotypes to be used as parents in breeding programs
How much valuable genetic variation for target traits in
the primary gene pool for breeding remains unclear!
- Few accessions with desirable phenotypes for most traits
- No accessions with desirable phenotypes for certain traits
Reasons for Poor Utilization of Germplasm
� Outstanding commercial genotypes are commonly
destroyed by crosses with unimproved exotic germplasm
� Utilization – very poorly
- Less than 5% of the collected germplasm in the Genebanks
have been utilized in the worldwide breeding programs
destroyed by crosses with unimproved exotic germplasm
(Duvick 1984)
� Selection of parental lines in breeding programs are largely
based on phenotype and very few accessions appear to have
“desirable” phenotype for complex traits
� Slow but consistent genetic improvement can still be
achieved even within a narrow base in many breeding
programs
� To exam if there is sufficient (novel) genetic
variation for target traits in the primary gene
Objectives
The GSR Breeding Strategy: Exploiting
the maximum genetic diversity in the
primary gene pool of rice
variation for target traits in the primary gene
pool for most complex traits
� If yes, to develop an effective and efficient strategy
to exploit the genetic diversity for complex traits
- Generation of information and training personnel
- Integration with the molecular tools
- Integration with gene discovery
Full Exploitation of The Genetic Diversity in the
Primary Gene Pool of Rice
The Basic Idea
The GSR Breeding StrategyDonors
(203 WMCC, 300 CMC +
20 wild rice accessions)
Recipients(46 best commercial
Varieties and hybrid parents)
X
BC breeding to introgress
superior alleles from MCC into
elite genetic backgrounds
Trait-specific
IL sets in elite GBs
Genotyping by re-
sequencing of all
parents
Molecular database
of the parents
Genotyping &
Parents for next
round of DQP
Genotyping &
phenotyping
Genetic characterization
of ILs
Development of
new cultivars
and PL setsBreeding by MRS
or DQP
Release to
farmers
-omics and
bioiformatics
Theory and
technology of
breeding by
molecular design
Gene networks and metabolic
pathways of the target traits and
functional diversity of alleles at the loci
The Chinese GSR research institutions - China
National Rice Molecular Breeding Network
Goal
The goal of NCMBN was to develop
superior inbred and hybrid crop
cultivars with significantly improvedcultivars with significantly improved
yield stability, yield potential, and
grain quality for the major rice
growing areas in China.
Specific objectives
� To broaden the genetic base of crop cultivars in major crop
growing areas of China by maximizing the gene flow from the
primary rice gene pool into elite genetic backgrounds through
backcross breeding;
� To exploit the hidden diversity of the primary rice gene pool
for improving complex target traits;for improving complex target traits;
� To develop IL sets for important traits in elite rice genetic
backgrounds;
� To discover and characterize large numbers of QTLs and
QTL networks underlying important traits, and to mine
allelic diversity at important QTLs;
� To establish genetic/phenotypic database for the ILs;
� To train a new generation of molecular rice breeders in China.
Proof of the Concept
• How much useful genetic diversity,
particular for the complex
phenotypes, within the primary
gene pool of rice?
Two Fundamental Questions:
gene pool of rice?
• Can we combine the process of
breeding with gene discovery
(gene/QTL discovery and allelic
mining)?
Part I: Introgression breeding
and mass selection
Recurrent Parents
IR64 - Indica, high yield/widely adaptable
New Plant Type - Japonica, high yield potential
Teqing - Indica, high yield/widely adaptable
The “value” added and base broadening
approach – Introgression breeding
Widely
adaptable
high yield
Add new genes/traits
by backcross breedingIR64 introgression
lines with improved
target traitshigh yield
varieties (IR64)
target traits
Discovery of desirable QTLs using
DNA markers and MAS for
pyramiding QTLs
IR64 lines with improved
target traits and the “same”
yield potential and quality
Procedure of the backcross breeding for development of ILs for
gene/QTL identification and cultivar development
RP x donors F1s x RP 25 BC1F1s x RP
~25 BC1F2s x RP
Bulk BC1F2 populations
~25 BC2F1s x RP
Self and bulk
harvest
Self and bulk
harvest
X
1, 2, 3, 4, 5, nScreen for
target traits:
X
Bulk BC2F2 populations
1, 2, 3, 4, 5, n
Large numbers of ILs with selected target traits in the elite RP genetic background
Replicated progeny testing for the introgression lines (ILs) for the selected target traits (tolerances to
drought, salinity, submergence, BPH, etc), and for yield performances and other agronomic traits under
non-stress conditions
Best ILs with selected target trait(s)
used as parental lines for
pyramiding genes/QTLs from
different donors
Genotyped w/ DNA markers to track the gene
flow and to identify genes/QTLs for the target
traits
Promising ILs with selected target
trait(s) and good yield performances
nominated for NCTs
Development and releases of
green super rice cultivars for
specific target environments
To rice farmers in the target
environments
Four Major Groups of Target Traits
� Tolerances to abiotic stresses (drought,
salinity, low and high temperatures, N
and P use efficiency, etc.)
� Resistances to biotic stresses (blast, � Resistances to biotic stresses (blast,
sheath blight, false smut, BPH, stem
borer, BB, etc.)
� Yield potential and heterosis
� Quality parameters
Donor gene pool (203 accessions from
34 countries)
Sub-G1 (54)
Sub-G2 (6)
Sub-G3 (33)
Sub-G4 (46)
I (indica)
Sub-G4 (46)
Ba-Bao-Mi (Yunnan)
Sub-G5(15)
Sub-G6 (12)
Sub-G7 (28)
Sub-G8 (9)
Jalmagna (India)
II (japonica)
III (New group)
Europe
NA
America Others
15%NA
Europe America Others
10%
Proportions of accessions
from different geographic
regions
Relative genetic diversity of
accessions in different
geographic regions
Gene diversity of the donor gene pool
SA
33%China
22%
SEA
30%
NA
SA
40%China
26%
SEA
24%
NA
Target traits
• Tolerances to drought, salinity, submergence,
zinc deficiency, phosphorus deficiency,
anaerobic germination, etc.
• Resistances to BB, BPH, blast, tungro, sheath • Resistances to BB, BPH, blast, tungro, sheath
blight, etc.
• Different maturities
• Different types of grain quality parameters
• Yield and related traits
BC Breeding Procedure
RP Donors of diverse originsX
F1s
BC1F1
X RP
X RP
BC F
Selection for target traits
Survival plants GenotypingProgeny testing
x
BC2F1
BC2F2 bulk populations
Major differences of introgression breeding and
the conventional BC breeding
BC breeding Marker aided
BC breeding
Introgression
breeding
RP selection Elite Same Same
Donor selection Yes Yes No/diverse
Target traits Single Single or few No limitationTarget traits Single
monogenic/dominant
Single or few No limitation
Selection Mass selection MAS Mass selection
Progeny testing yes yes yes
Pop. size Small Small Regular
Selection efficiency High High Depends
Breeding efficiency Low Low High
Selection strategy for target
traits in random BC
progeniesprogenies
Stress for 20 days (March 27,2001) Stress for 56 days (May 2, 2001)
Screening of BC2F2 populations for tolerance
to terminal drought at the reproductive stage
under the lowland conditions
Variation in BC2F2 populations for drought
tolerance under the lowland conditions
Summary of selected drought tolerant BC2F2 plants
under lowland stress conditions
Total plants selected
NPT IR64 Teqing
897 2775 489
Total
4161
# of selected plants
per population
8.5
(3.8%)
22.4
(10.0%)
6.3
(3.0%)
13.2
(6.8%)
Range
No. of I donors
0 - 85 0 - 100 0 - 30 0 - 100
59 67 59 185
per population (3.8%) (10.0%) (3.0%) (6.8%)
No. of J donors 32 45 19 96
No. of populations 113 124 105 320
Contributing donor (%) 80.5 90.3 74.3 87.8
The Screening of BC2F2 populations
under upland drought conditions
The RP, IR64
Total plants selected
IR64 Teqing
192 334
Total
526
Summary of selected drought tolerant BC2F2 plants
under lowland stress conditions
Ave. selected plants
Per population9.6 (4.6%) 10.8 (5.2%) 10.3 (5.0%)
Range
No. of I donors
4 - 20 3 - 15 4 - 30
12 23 35
No. of J donors 8 8 16
No. of populations 20 31 51
Contributing donor (%) 100 100 100
Parental performances and 442 selected DT BC2F2plants for drought tolerance from 19 BC populations
VG Donors IR64 (S) Teqing (M) NPT(SS)
I BR24 (S) 14 (27) 12 (7) 3
I STYH (S) 20 (26) 4
I OM1723 (S) 7 (17) 7 (6) 0
TotalOrigin
Bangladesh
Myanmar
Vietnam
29 (34)
LL (UL) LL (UL) LL
24 (26)
14 (23)
-
J FR13A (SS) 15 (16) 17 (15) 0
J Type3 (SS) 23 (15) 10 (12) 0
J Binam (M) 20 (19) 14 (13) 1
J HAN (M) 11 (13) - 3
Zihui100 (S) 8 - 9I
Total
Khazar (S)J
India
India
Iran
China
China
Iran
32 (31)
33 (27)
35 (32)
14 (13)
58 58
17
176 (133) 60 (53) 22 256 (186)
-
Screening of BC2F2 populations for salinity
tolerance at the seedling stage
ST CK
Pokali
Young seedlings were subjected to:
6 dSm-1 for 3 days, 12 dSm-1 for 2 weeks, 18
dSm-1 for 1 week, and 24 dSm-1 for 1 week
IR64
Confirmation by progeny testing
Seedling screening at EC 24 dSm-1 for 3 weeks
Table 1. Summary results of BC populations for screening salinity tolerance
Details BC2F2 screening BC2F3 reconfirmation
IR64 Teqing NPT Total IR64 Teqing NPT Total
Total BC2F2 populations 62 58 55 175 24 34 10 68
Single plant selections per BC
population 4 - 12 4 - 13 1 - 14 0 - 43 0 - 49 0 - 11
Total selected BC2F3 lines 490 428 374 1292 448 392 21 861
Selection intensity (%) 3.95 3.69 3.40 3.69
Number of indica donors 47 47 42 136 20 27 7 54
Selected lines 369 345 289 1003 372 269 21 662
Selection intensity (%) 4.39 3.67 3.44 3.69
Number of japonica donors 9 9 7 25 3 6 1 10
Selected lines 70 66 44 180 43 123 0 166
Selection intensity (%) 3.89 3.67 3.14 3.60
Number of intermediate donors 4 1 3 8 1 1 2 4
Selected lines 35 5 19 59 33 0 0 33
Selection intensity (%) 4.38 2.50 3.16 3.69
BC2F2 screening BC2F3 reconfirmation
# of BC2F2 pop. 62 58 55 175 24 34 10 68
# of selections per pop. 4 - 12 4 - 13 1 - 14 1 - 14 0 - 43 0 - 49 0 - 11
IR64 Teqing NPT Total IR64 Teqing NPT Total
Summary results of BC populations
for screening salinity tolerance
# of selections per pop. 4 - 12 4 - 13 1 - 14 1 - 14 0 - 43 0 - 49 0 - 11
Total selected lines 490 428 374 1292 448 392 21 861
# of contributing
donors 60 57 52 169
SI (%) 3.95 3.69 3.40 3.69
For individual BC populations of 200 plants, a difference of 4% between two populations in
selection intensity (survival rate) is statistically significant at P < 0.05 when the selection
intensity is between 0.1 and 0.5.
Screening of BC2F2 populations for
submergence tolerance in a deep-water pond
Thirty-five-day old seedlings were submerged under deep water
for two weeks, then allowed to recover
# of BC pop. 47 47 36 130 60 57 62 179
Anaerobic germination Submergence
IR64 Teqing NPT Total IR64 Teqing NPT Total
Summary results of BC populations
for screening anaerobic germination
and submergence tolerance
# of BC pop. 47 47 36 130 60 57 62 179
# of selections per pop. 0 - 5 0 - 6 0 - 14 0 - 15 3 - 13 0 - 12
Total selected lines 47 81 215 343 652 483 530 1665
# of contributing
donors 46 46 35 127 59 57 60 176
SI (%) 0.52 0.93 3.11 1.32 1.08 0.85 0.85 0.93
Screening of BC2F2 populations for
anaerobic germination
Direct seeding then submerged under 10 cm-deep water
Summary results of BC populations screened for anaerobic
germination and submergence tolerance
Details Anaerobic germination Submergence
IR64 Teqing NPT Total IR64 Teqing NPT Total
Total BC2F2 populations 47 47 36 130 60 57 62 179
Single plant selections per BC
population 0 - 5 0 - 6 0 - 14 0 - 15 3 - 13 0 - 12
Total selected BC2F3 lines 47 81 215 343 652 483 530 1665
Selection intensity (%) 0.52 0.93 3.11 1.32 1.08 0.85 0.85 0.93 Selection intensity (%) 0.52 0.93 3.11 1.32 1.08 0.85 0.85 0.93
Number of indica donors 37 38 29 104 47 50 50 147
Selected lines 31 67 77 175 538 431 451 1411
Selection intensity (%) 0.43 0.90 3.10 0.84 1.15 0.86 0.90 0.96
Number of japonica donors 6 8 5 19 8 7 7 22
Selected lines 11 14 31 56 83 52 63 198
Selection intensity (%) 0.91 1.03 3.10 1.47 1.00 0.74 0.90 0.90
Number of intermediate donors 3 0 1 4 4 0 3 7
Selected lines 5 0 7 12 40 0 16 56
Selection intensity (%) 0.83 0.00 3.50 1.50 1.04 0.00 0.53 0.80
Screening for BPH Resistance
IR64
Summary results of BC populations screened for low temperature
germination and brown planthopper resistance
Details Low temperature germination Brown planthopper resistance
IR64 TQ NPT Total IR64 TQ NPT Total
Total BC2F2 populations 14 15 10 39 64 67 62 193
Single plant selections per BC
population 0 - 21 0 - 18 0 - 31 0 - 22 0 - 22 0 - 2
Total selected BC2F3 lines 79 77 51 207 652 255 2 909
Selection intensity (%) 5.64 5.13 5.10 5.31 10.19 3.81 0.03 4.71
Number of indica donors 1 1 0 2 49 60 49 158Number of indica donors 1 1 0 2 49 60 49 158
Selected lines 0 3 0 3 565 221 2 788
Selection intensity (%) 0.00 3.0 0.00 1.5 11.53 3.68 0.04 4.99
Number of japonica donors 9 11 7 27 9 11 7 27
Selected lines 55 52 39 146 54 21 0 75
Selection intensity (%) 6.11 4.73 5.57 5.41 6.00 1.91 0.00 2.78
Number of intermediate donors 4 3 3 10 4 3 3 10
Selected lines 24 22 12 58 33 2 0 35
Selection intensity (%) 6.00 7.33 4.00 5.80 8.25 0.67 0.00 3.50
For individual BC populations of 100 plants, a difference of 2.5% between two populations in selection
intensity (survival rate) is statistically significant at P < 0.05 when the selection intensity is < 0.1.
# of BC2F2 pop. 14 15 10 39 64 74 62 200
# of selections per pop. 0 - 21 0 - 18 0 - 31 0 - 22 0 - 22 0 - 2
Low temperature germination BHP resistance
IR64 Teqing NPT Total IR64 Teqing NPT Total
Summary results of BC populations for screening
low temperature germination and BPH resistance
# of selections per pop. 0 - 21 0 - 18 0 - 31 0 - 22 0 - 22 0 - 2
Total selected lines 79 77 51 207 652 255 2 909
# of contributing
donors 14 14 10 38 62 67 59 189
SI (%) 5.64 5.13 5.10 5.31 10.19 3.81 0.03 4.71
For individual BC populations of 200 plants, a difference of 4% between two populations in
selection intensity (survival rate) is statistically significant at P < 0.05 when the selection
intensity is between 0.1 and 0.5.
Screening for tolerance to phosphorus
deficiency
Tested in natural conditions in Pangil, Laguna.
Screening for tolerance to zinc deficiency
Summary results of BC populations screened for zinc deficiency tolerance
Details BC2F2 screening under moderate field stress
BC2F4 progeny testing under very severe
field stress
IR64 Teqing NPT Total IR64 Teqing NPT Total
Total number of BC populations 51 42 36 129 11 21 10 42
Single plant selections per BC
population 4 - 12 2 - 12 0 - 12 0 - 12 0 - 10 0 - 15 0
Total selected BC2F3 lines 454 383 324 1161 72 255 0 327
Selection intensity (%) 7.42 7.60 7.50 7.50 2.14 2.41 0.00 2.01 Selection intensity (%) 7.42 7.60 7.50 7.50 2.14 2.41 0.00 2.01
Number of indica donors 40 33 25 98 9 17 9 35
Selected lines 370 320 237 927 63 200 0 263
Selection intensity (%) 7.77 8.08 7.90 7.88 2.07 2.31 0.00 1.91
Number of japonica donors 7 6 7 20 1 4 1 6
Selected lines 63 63 84 210 0 55 0 55
Selection intensity (%) 7.50 8.75 7.86 8.75 0.00 2.86 0.00 2.29
Number of intermediate donors 3 - 1 4 1 0 0 1
Selected lines 21 - 9 30 9 0 0 9
Selection intensity (%) 5.83 - 7.50 6.25 5.63 0.00 0.00 5.63
Selection for changed grain
type of Teqing
Selection for high
yield
High tiller number
Screening for blast resistance
Low N stress
experiment
under rain-off
shelter
Improving japonica for cold
tolerance at the reproductive stage
Donor parent Subspecies CodePopulation
size
No. of
selected
plants
SI 1
(%)
SF (%)
Mean ± SD2 Range
Bg90-2 Indica A 450 41 9.1 63.3±8.4D 50.3-86.5
X21 Indica B 450 29 6.4 64.3±9.9CD 50.6-87.1
X22 Indica C 450 28 6.2 65.6±10.1BCD 50.7-87.3
Screening results of 11 CY1 (recurrent parent) BC2F4 backcross populations for cold
tolerance at the booting stage in 2008 (1 SI = selection intensity, SF = spikelet
fertility; 2 Different letters indicate statistical significance at P < 0.05, based on the
Duncan testing)
X22 Indica C 450 28 6.2 65.6±10.1BCD 50.7-87.3
Q5 Indica D 450 31 6.9 71.1±11.1ABC 50.9-91.4
Chhomrong Japonica E 450 24 5.3 75.6± 51.4-87.8
Doddi Indica F 450 25 5.6 71.0±10.0ABC 50.2-90.0
Fengaizhan Indica G 450 44 9.8 74.1± 52.2-98.5
Shennong265 Japonica H 450 21 4.7 69.2±11.4ABCD 50.7-93.8
Yuanjing7 Japonica I 450 41 9.1 71.1±9.8ABC 50.0-90.1
OM997 Indica J 450 21 4.7 72.1±9.1AB 54.9-89.6
Cs94 Indica K 450 19 4.2 64.2±8.6CD 51.4-86.0
Mean 450 29.5 6.5 69.2±4.2
CY1 Japonica 324 24.8±4.3E 19.0-30.0
Screening of the BC2F4 bulk populations for cold tolerance
(CT) at the booting stage:
Seeds of the BC2F4 bulk populations were sown in the seedling nursery on April
15, 2008, and 450 40-day old seedlings of each BC2F4 bulk population were
transplanted into a 45-row plot with 10 plants in each row and a spacing was
25×15cm in the sheltered water pond of JAAS on May 25. Two rows of CY1
were also transplanted on both sides of each plot as the checks. The water-pond
were irrigated with water of normal temperature (25~28℃). When CY1 entered
℃℃℃℃
were irrigated with water of normal temperature (25~28℃). When CY1 entered
the stage of panicle initiation, the LT treatment was initiated by irrigation of
flowing cold water (19±±±±0.5℃℃℃℃), which was adjusted in a nearby water pool by mixing cold underground water (9℃℃℃℃) with the river water. The depth of the
cold water in the pond was 20cm and the treatment was maintained for ~30
days until panicles of almost all plants exerted completely. Then, irrigation
with normal temperature water was resumed until the maturity. At the
maturity, all plants except those with >3 days earlier heading or those with
>3 days delayed heading than CY1 were harvested for measuring the
spikelet fertility. Under this LT treatment, CY1 had a spikelet fertility of
24.8±±±±4.3%, then, any plant with spikelet fertility >50% were selected.
Donor parent
No. of
selected
lines
Cold stress at the seedling
stage Cold stress at the reproductive stage
Survival rate of seedlings
(%) SNP FGN SF (%)
Mean Range Mean Range Mean Range Mean Range
BG90-2 41 19.5 10.0~62.5 114.5 76.3~164.2 55.0 22.1~95.7 48.0 18.5~71.3
X21 29 19.4 11.1~40.3 99.7 73.3~125.0 50.5 29.5~90.3 50.3 30.9~74.9
X22 28 19.6 12.5~40.7 113.2 70.3~139.0 58.5 4.5~94.9 51.4 5.6~79.4
Q5 31 18.3 15.0~33.8 114.6 68.3~185.4 56.5 15.3~113.6 49.2 14.6~83.6
Evaluation of 324 BC2F6 introgression lines and their recurrent parent, CY1 for cold
tolerance of at the seedling and booting stages in 2009 (SNP = spikelet number per panicle,
FGN = filled grain number per panicle, SF = spikelet fertility)
Q5 31 18.3 15.0~33.8 114.6 68.3~185.4 56.5 15.3~113.6 49.2 14.6~83.6
Chhomromg 24 17.0 15.0~32.5 109.8 77.6~175.2 74.0 47.0~104.8 66.9 45.6~83.4
Doddi 25 17.3 12.5~25.0 112.9 89.4~182.6 73.9 51.5~108.5 65.4 48.7~80.6
Fengaizhan 44 16.7 12.5~25.0 96.5 70.2~115.1 67.1 14.3~96.0 70.1 12.7~86.1
Shennong265 21 15.6 0.0~23.3 96.9 65.0~144.8 62.0 36.9~99.2 63.0 40.0~79.9
Yuanjing7 41 18.5 15.0~45.0 116.0 93.5~151.0 80.6 30.4~106.4 69.2 25.5~84.2
OM997 21 37.1 15.0~82.4 81.6 56.2~108.1 42.0 14.9~64.0 51.1 23.3~72.0
Cs94 19 22.3 15.0~42.5 113.3 82.0~137.9 69.5 31.8~99.4 60.0 34.2~75.5
CY1 14.8 10.8~20.0 106.6 98.6~114.6 36.7 32.7~40.8 35.1 33.7~36.5
LSD0.05 4.5 8.3 8.2 6.2
PopulationN1
The reproductive stage The seedling stage
FGN SNP SF (%) SR (%)
Code Donor N1 N2 N1 N2 N1 N2 N1 N2
A BG90-2 41 18 0 13 6 17 1 5 0
B X21 29 7 0 0 3 15 0 4 0
C X22 28 17 2 8 1 17 3 5 0
D Q5 31 15 2 10 4 20 3 1 0
E
Comparison of selection efficiencies of 11 CY1 BC2F6 populations for cold
tolerances at the seedling and reproductive stages
E Chhomromg 24 17 0 7 3 22 0 2 0
F Doddi 25 23 0 1 0 24 0 0 0
G Fengaizhan 44 35 1 0 7 42 1 0 0
H Shennong265 21 12 0 2 9 18 0 0 1
I Yuanjing7 41 40 0 9 0 40 0 3 0
J OM997 21 2 1 0 13 13 0 14 0
K Cs94 19 14 0 5 1 14 0 6 0
Total 324 200 6 55 47 242 8 40 1
1 N is the total number of selections based on single plant spikelet fertility (SF) in BC2F4 populations from Table 1, N1 and N2 are the numbers of the BC2F6 lines
showing significantly higher or significantly lower than CY1 for the measured traits. FGN, SNP, SF and SR are filled grain number per panicle, spikelet number
per panicle, spikelet fertility and survival rate of seedlings.
Trait 1 Chhomrong Doddi Fengaizhan Shennong265 Yuanjing7 Mean CK
N 24 24 24 20 24 116
Under the normal conditions
PH (cm) 135.2±±±±4.4 130.6±±±±5.8 125.7±±±±5.4 127.2±±±±3.7 132.3±±±±4.5 130.3 117.1
BM (g/plant) 37.1±3.3 36.5±3.4 38.1±3.5 33.5±3.3 35.1±2.4 36.2 34.7
FGN 143.4±15.0 143.7±17.2 148.1±12.3 135.1±15.6 156.3±±±±19.4 145.7 138.9
SNP 176.6±20.8 179.4±20.9 171.2±17.4 172.9±17.7 197.2±±±±21.8 179.7 168.6
SF (%) 81.6±6.6 80.4±8.1 86.9±±±±5.8 78.4±7.2 79.2±5.3 81.4 82.4
GY (g/plant) 19.4±±±±2.94 20.5-3.0 20.9±±±±2.5 18.7±±±±2.5 18.7±±±±2.7 19.6 19.7
HI (%) 55.0±5.2 59.1±4.9 57.9±3.7 59.1±4.4 56.0±4.8 57.3 60.3
PN 5.4±0.6 5.7±0.4 5.7±0.6 5.6±0.7 4.8±±±±0.5 5.5 5.7
Mean performances of 116 ILs of five populations for 11 traits evaluated under
normal and cold water stress conditions in 2010
PN 5.4±0.6 5.7±0.4 5.7±0.6 5.6±0.7 4.8±±±±0.5 5.5 5.7
GW (g) 24.3±1.5 26.3±±±±1.6 22.0±±±±2.1 24.5±1.1 26.3±±±±1.4 24.7 24.9
HD (d) 113.9±3.3 113.0±4.1 116.3±6.0 112.5±4.7 113.6±3.9 113.9 111.1
Under the cold water stress
PH (cm) 118.1±±±±7.9 119.9±±±±7.7 119.8±±±±7.7 122.4±±±±6.6 125.2±±±±5.7 121.0 107.8
BM (g/plant) 16.2±3.2 16.1±2.7 16.8±2.5 15.3±3.6 17.5±3.6 16.4 12.0
FGN 46.8±28.4 39.1±20.2 63.8±±±±14.3 22.9±±±±14.1 46.4±19.8 44.5 12.8
SNP 118.9±23.9 121.7±13.8 110.4±12.9 117.7±24.1 139.6±19.6 121.8 121.5
SF (%) 38.8±18.3 32.3±14.5 57.3±±±±10.3 19.7±±±±12.1 33.3±14.6 36.9 10.5
GY (g/plant) 3.5±±±±2.2 3.0±±±±1.7 5.0±±±±1.3 1.9±±±±1.2 3.6±±±±1.9 3.5 1.0
HI (%) 33.3±7.6 30.7±6.7 40.9±±±±4.4 25.8±±±±7.2 30.8±5.1 32.5 25.1
PN 3.3±0.5 3.4±0.6 3.3±0.5 3.7±0.9 3.2±0.5 3.4 3.5
GW (g) 17.9±1.5 18.0±1.6 17.5±2.7 17.1±0.9 17.9±1.3 17.7 16.4
HD (d) 131.3±2.2 128.2±3.3 132.0±4.1 126.9±4.1 128.6±3.0 129.5 125.2
Donor N1 TreatBM (g/plant) FGN
GY
(g/plant)
GW
(g)
HD
(d)
HI
(%)
PH
(cm)PN
SF
(%)SNP
N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2
Chhomrong 24
S
18 0 18 0 14 0 15 0 24 0 14 0 19 2 3 8 21 0 6 12
Doddi 24 18 0 19 0 15 0 16 1 16 2 14 2 21 0 5 7 19 0 4 4
Fengaizhan 24 22 0 24 0 23 0 6 3 22 1 24 0 20 0 2 6 24 0 0 12
Shennong26
5 20 12 1 7 0 6 0 5 2 10 8 7 6 18 0 9 5 10 0 6 8
Yuanjing7 24 21 0 21 0 19 0 17 0 16 0 15 1 24 0 3 8 20 0 12 1
The numbers of ILs from the 5 populations that deviated significantly CY1 for 11
measured traits evaluated under cold water stress (S) and normal (N) conditions in 2010
Total 116 91 1 89 0 77 0 59 6 88 11 74 9 102 2 22 34 94 0 28 38
Chhomrong 24
N
15 2 11 5 9 8 4 13 13 2 1 16 24 0 3 9 7 9 11 4
Doddi 24 11 4 10 5 9 5 17 4 11 3 6 7 24 0 4 4 8 12 13 5
Fengaizhan 24 16 0 14 2 9 1 2 20 19 3 3 15 21 0 5 7 15 4 8 8
Shennong26
5 20 3 8 5 7 2 9 5 10 8 7 5 7 20 0 8 10 5 13 9 7
Yuanjing7 24 5 3 17 2 5 14 18 2 11 3 3 18 24 0 0 21 4 12 20 1
Total 116 50 17 57 21 34 37 46 49 62 18 18 63 113 0 20 51 39 50 61 25
1 N is the total number of ILs with CT selected from each population; N1 and N2 are the numbers of the ILs showing significantly higher and lower trait
values than CY1.
GY = grain yield, BM = biomass, PH = plant height, PL = panicle length, PN = panicle number per plant, FGN = filled grain number per panicle, SNP =
spikelet number per panicle, SF = spikelet fertility, HD = heading date, GW = 1000-grain weight, HI = harvest index.
Line# Pop.12010 under the normal condition 2010 under cold water stress 2009 under stress
PH BM SNP SF GY HI PN GW HD PH BM SNP SF GY HI PN GW HD SNP SF SR
CK(CY1) 117.1 34.7 168.6 82.4 19.7 60.3 5.7 24.9 111.1 107.8 12.0 121.5 10.5 1.0 25.1 3.5 16.4 125.2 106.6 35.1 14.8
LW213 G134.2 48.5 192.3 91.1 28.1 60.1 6.4 22.8 103.0 129.2 19.5 131.2 69.1 7.2 46.8 3.5 15.7 128.0 101.7 81.2 12.5
LW164 F126.5 45.7 204.5 87.8 28.5 65.2 6.4 23.5 117.0 118.8 17.2 120.0 27.3 2.5 26.0 3.3 16.1 129.0 113.2 56.9 15.0
LW180 F131.7 38.8 182.0 89.8 23.4 63.1 5.7 25.6 101.0 131.7 18.0 138.0 39.6 4.9 36.3 3.3 19.1 123.0 107.3 68.0 17.5
LW157 F133.4 41.0 218.7 71.9 23.4 59.9 6.0 25.2 116.0 114.8 20.9 132.8 40.1 5.0 33.8 4.3 17.1 131.0 110.6 60.3 17.5
LW170 F129.3 40.0 183.3 83.7 22.8 59.7 5.9 24.0 117.0 117.8 19.6 119.5 45.5 5.3 38.4 4.8 16.7 131.0 118.4 71.9 17.5
LW214 G122.0 38.0 159.8 85.6 22.9 63.5 6.7 17.9 120.0 108.5 14.3 103.7 54.9 4.5 44.4 3.3 16.3 137.0 86.7 84.5 15.0
LW188 G121.0 40.1 164.3 84.2 23.1 60.6 6.7 21.0 121.0 130.0 16.6 119.7 66.9 5.8 46.2 3.2 17.0 138.0 90.9 82.5 15.0
LW142 E
Mean performances of 19 promising ILs under cold water stress and
normal conditions in 2009 and 2010 (Meng et al. 2012)
LW142 E136.7 39.3 162.7 79.2 21.5 57.7 6.7 23.9 112.0 121.5 16.7 119.8 61.6 5.2 43.1 3.2 18.1 134.0 91.2 60.0 15.0
LW154 E137.8 39.9 198.3 82.9 21.9 58.0 5.4 23.4 112.0 128.5 19.7 160.7 67.4 7.4 47.7 3.0 17.4 130.0 121.6 71.3 15.0
LW174 F129.5 37.6 151.3 86.6 21.7 61.0 6.7 25.9 115.0 120.3 17.7 122.0 48.2 5.3 41.4 4.2 17.8 128.0 126.2 80.3 25.0
LW207 G132.6 40.0 192.8 79.9 22.1 58.0 5.8 21.2 121.0 127.0 20.1 118.3 66.6 6.7 43.1 3.8 17.5 132.0 115.1 83.7 20.0
LW264I
138.8 40.7 221.5 77.7 22.6 58.0 5.3 24.9 107.0 130.0 17.2 169.2 26.3 3.1 29.1 2.8 17.9 125.0 120.3 79.1 42.5
LW250 I130.7 39.2 226.8 79.9 23.3 62.6 5.2 26.0 110.0 136.8 20.1 136.8 65.1 5.8 38.4 2.7 18.0 132.0 108.4 76.1 20.0
LW156 E138.9 40.3 187.8 78.9 21.0 55.0 5.7 23.0 114.0 127.0 20.2 129.7 57.9 6.8 43.0 4.0 16.3 129.0 131.8 74.0 15.0
LW151E
131.9 37.7 168.3 82.9 19.2 53.9 5.6 24.2 114.0 122.3 19.3 123.5 67.2 6.6 43.3 3.3 16.6 130.0 122.4 82.9 16.3
LW189 G132.4 37.9 198.3 84.4 20.1 55.9 4.8 21.7 120.0 133.2 19.0 114.7 59.5 6.2 41.1 3.5 17.0 137.0 103.4 75.7 20.0
LW216G
129.1 37.3 170.8 87.1 20.1 56.9 5.4 20.7 123.0 111.8 17.1 99.8 51.7 4.3 34.4 2.8 15.9 139.0 99.9 86.1 16.9
LW200G
127.7 38.6 167.8 88.8 20.5 56.1 5.6 20.3 115.0 122.0 16.4 100.2 66.2 4.9 41.9 3.3 16.5 130.0 93.7 84.2 17.5
LW291I
121.1 33.1 181.5 84.8 17.5 56.5 4.7 25.1 120.0 126.3 24.9 156.3 39.1 6.6 32.2 4.2 17.7 131.0 143.6 74.5 45.0
LSD0.05 1.9 2.1 8.2 2.6 1.6 1.8 0.3 0.5 1.9 3.7 1.8 11.1 8.1 1.2 4.3 0.4 1.1 1.6 8.2 6.2 4.5
The hidden diversity for highly
heritable traits – BLB resistance
P1 P2 P3b P3c P4 P5 P6 P7 P8 P9a P10 P9c P9b P9d
PXO
61
PXO
86
PXO
79
PXO
340
PXO
71
PXO
112
PXO
99
PXO
145
PXO
280
PXO
339
PXO
341
PXO
347
PXO
349
PXO
363
aver
age
HHZ 9.8 21.2 13.1 25.7 10.4 2.4 29.6 5.0 8.6 28.8 8.4 26.6 15.2 24.6 16.4
Reactions (lesion lengths) of HHZ and two donors to 14
tropical races of BLB caused by Xanthomonas oryzae pv oryzae
HHZ 9.8 21.2 13.1 25.7 10.4 2.4 29.6 5.0 8.6 28.8 8.4 26.6 15.2 24.6 16.4
PSBRC66 6.4 18.5 16.4 21.4 11.6 0.7 13.0 2.6 8.8 4.1 7.0 12.0 3.4 17.3 10.2
PSBRC28 2.8 20.3 21.6 24.0 11.2 3.9 22.4 4.7 9.2 26.0 8.5 23.7 22.9 21.9 15.9
8个黄华占群体对15个Xoo菌株产生反应类型(2012年8月,北京)
对全部15个小种高抗的株系 对全部15个小种感病的株系对部分小种抗病的株系
F1F1F1F1----F5F5F5F5 F6F6F6F6----F10F10F10F10 F11F11F11F11----F15F15F15F15 F1F1F1F1----F5F5F5F5 F6F6F6F6----F10F10F10F10 F11F11F11F11----F15F15F15F15 F1F1F1F1----F5F5F5F5 F6F6F6F6----F10F10F10F10 F11F11F11F11----F15F15F15F15
Blast evaluation of virulent strainsBlast evaluation of virulent strains Evaluation of BB resistance of >500 Evaluation of BB resistance of >500
lines (HHZ background) against 14 lines (HHZ background) against 14
strains of 10 strains of 10 XooXoo races, 2010 WSraces, 2010 WS
HHZ is
susceptible to
most tropic
BLB races
Vera Cruz et al
PX
O61
PX
O86
PX
O79
PX
O34
0
PX
O71
PX
O11
2
PX
O99
PX
O14
5
PX
O28
0
PX
O33
9
PX
O34
1
PX
O34
7
PX
O34
9
PX
O36
3
aver
age
HHZ 9.8 21.2 13.1 25.7 10.4 2.4 29.6 5.0 8.6 28.8 8.4 26.6 15.2 24.6 16.4
PSBRC66 6.4 18.5 16.4 21.4 11.6 0.7 13.0 2.6 8.8 4.1 7.0 12.0 3.4 17.3 10.2
HHZ15-SAL13-Y2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ15-SAL-13-Y3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ15-DT7-SAL1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Ten HHZ ILs with broad spectrum resistance to all 14 races
of bacterial blight pathogen, Xanthomonas oryzae pv oryzae
HHZ15-DT7-SAL1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ15-DT7-SAL3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ15-DT7-SAL6 0.2 0.2 0.2 0.2 9.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.9
PSBRC28 2.8 20.3 21.6 24.0 11.2 3.9 22.4 4.7 9.2 26.0 8.5 23.7 22.9 21.9 15.9
HHZ19-SAL-14-Y3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ19-DT8-SAL2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
HHZ19-SAL12-
SAL4 0.2 0.7 0.9 0.5 0.2 0.2 0.2 0.2 0.4 0.2 0.3 0.9 0.2 0.2 0.4
HHZ19-SAL14-
SAL4 0.2 1.0 0.6 0.3 0.2 0.2 0.2 0.2 0.3 0.2 0.7 0.2 0.2 0.2 0.3
HHZ19-SAL15-
SAL2 0.2 3.8 2.2 0.6 0.4 0.4 0.8 0.5 0.3 0.3 0.3 0.6 0.4 0.4 0.8
Race R% (LL <3.0 cm)
P1 76.4
P2 4.7
P3b 4.9
P3c 4.9
P4 22.4
P5 78.4
Reactions of 512 HHZ ILs to 14 tropical Xoo races
P5 78.4
P6 5.1
P7 46.6
P8 31.0
P9a 12.3
P10 12.1
P9c 4.7
P9b 5.1
P9d 50.8
P10
P8
P7
P4
P5
P1
Xooraces
Classification of 14 Xoo races into two major groups (virulent
and less virulent ones) based on the reactions of the 512 HHZ ILs
Weak virulence group
Average Distance Between Clusters
P9b
P9a
P3b
P3c
P6
P9c
P2
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3
Name Xoo
High virulence group
Name of lines
H12-33H12-12H9-63H11-27H8-45H19-9H12-15H12-7H12-4H12-9H11-24H12-48H11-55H11-11H19-35H12-36H11-54H8-54H5-60H12-31H15-11H8-18H5-55H15-30H9-4H17-53H19-56H15-24H12-54H15-25H15-8H19-36H19-59H9-66H19-50H19-57H15-21H12-64H15-19H17-5H12-55H12-61H12-40H11-50H8-38H9-9H17-34H19-14H11-16H9-51H19-29H12-18H19-46H12-20H9-41H12-24H19-15H11-31H19-13H19-55H17-35H15-43H9-70H11-28H12-2H19-45H12-39H11-49H11-45H11-34H11-36H11-30H11-32H12-16H8-55H9-40H12-26H11-10H17-32H5-26H19-23H19-22H9-56H19-18H12-17H8-26H8-40H9-18H8-41H5-6H9-25H9-14H8-47H5-59H8-31H8-21H5-51H9-24H15-26H5-5H8-33H12-27H17-11H19-48H8-3H5-13H5-12H9-26H9-16H8-51H8-13H9-7H8-23H8-8H15-1H5-49H17-29H15-12H8-44H5-32H9-13H9-3H17-65H9-20H8-27H5-1H9-39
Classification of the 512 ILs based on their resistances to the 14 Xoo Phillipines racesName of lines
Average Distance Between Clusters
H19-62H19-58H15-38H15-42H15-40H19-19H15-35H9-23H15-13H19-5H12-58H8-36H8-34H5-65H8-6H5-43H17-18H15-32H5-39H17-40H5-15H9-32H11-23H5-72H5-63H8-30H5-10H9-17H5-42H8-22H5-52H5-28H17-36H15-33H5-53H5-48H17-66H17-68H5-67H5-66H17-60H5-61H15-9H15-6H8-39H5-35H5-36H8-28H9-12H5-23H5-3H15-44H17-45H17-28H17-57H9-38H17-62H17-48H17-39H17-52H17-49H17-21H17-13H17-24H17-14H17-19H17-9H11-38H9-22H11-40H11-37H5-41H8-35H8-15H17-63H5-54H9-21H9-19H8-53H5-33H19-16H12-14H8-7H19-47H12-49H11-5H8-12H19-1H5-29H17-64H12-45H8-46H9-15H8-50H17-38H5-21H5-18H5-74H5-11H12-29H11-19H11-17H5-75H12-5H8-52H17-1H15-31H12-65H12-28H8-42H8-10H19-4H12-13H19-7H11-25H9-6H11-21H9-37H17-54H11-33H12-42H12-33H12-12H9-63H11-27H8-45
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Are the parental performances
correlated with the performances
of their BC progenies?
Genetic background effects in
introgression breeding
VG Donors TKM9 (SS)
(I)
Khazar (SS)
(I)
FR13A (T)
(J)
I IR64 (S) 12 8 14
TotalOrigin
India 34
Number of submergence tolerant plants in 9 BC2F2and 3 BC3F2 populations under the field condition
Submergence Tolerance
I Teqing (SS) 10 9 8
Total
NPT (SS)
BC2F2J
India
Iran
27
6 18
38 94 30 162
6 6
NPT (SS)
BC3F2J Iran 10 8371 2
15
20
25
Yield responses of the 193 parental lines of IRMBP
to the terminal drought under the lowland condition
-19.1±±±±44.0%
0
5
10
15
-100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160
Yield reduction (in %)
Summary of selected drought tolerant BC2F2 plants
under lowland stress conditions
Total plants selected
NPT IR64 Teqing
897 2775 489
Total
4161
# of selected plants
per population
8.5
(3.8%)
22.4
(10.0%)
6.3
(3.0%)
13.2
(6.8%)
Range
No. of I donors
0 - 85 0 - 100 0 - 30 0 - 100
59 67 59 185
per population (3.8%) (10.0%) (3.0%) (6.8%)
No. of J donors 32 45 19 96
No. of populations 113 124 105 320
Contributing donors (%) 80.5 90.3 74.3 87.8
Parental performance and 442 selected DT BC2F2plants for drought tolerance from 19 BC populations
VG Donors IR64 (S) Teqing (M) NPT(SS)
I BR24 (MR) 14 (27) 12 (7) 3
I STYH (S) 20 (26) 4
I OM1723 (S) 7 (17) 7 (6) 0
TotalOrigin
Bangladesh
Myanmar
Vietnam
29 (34)
LL (UL) LL (UL) LL
24 (26)
14 (23)
-
J FR13A (SS) 15 (16) 17 (15) 0
J Type3 (S) 23 (15) 10 (12) 0
J Binam (M) 20 (19) 14 (13) 1
J HAN (M) 11 (13) - 3
Zihui100 (S) 8 - 9I
Total
Khazar (MR)J
India
India
Iran
China
China
Iran
32 (31)
33 (27)
35 (32)
14 (13)
58 58
17
176 (133) 60 (53) 22 256 (186)
-
Comparison of different IR64 and NPT BC generations
in screening for anaerobic germination (%)
BC2F2 bulks BC3F2 bulks BC4F2 bulks
IR64 NPT IR64 NPT IR64 NPT
Total number of populations 9 10 - 10 9 10
Surviving plants/population 0 – 28 0 - 50 - 33 - 78 17 - 78 97 - 162
Number of indica donors 7 8 - 8 7 8Number of indica donors 7 8 - 8 7 8
Selected lines (indica) 36 158 - 452 296 1038
Selection intensity (%) 5.1 19.8 - 28.3 21.1 64.9
Number of japonica donors 2 2 - 2 2 2
Selected lines (japonica) 2 8 - 35 44 121
Selection intensity (%) 2.0 8.0 - 17.5 22.0 60.5
Mean selection intensity (%) 4.4 13.9 26.1 21.3 62.7
BC2F2, BC3F2 and BC4F2 bulks all had 200 seeds in 2 replications. For individual BC populations of
200 plants, a difference of 4% between two populations in selection intensity (survival rate) is
statistically significant at P < 0.05 when the selection intensity is between 0.1 and 0.5.
Screening for seedling cold tolerance
Twelve-day old seedlings were subjected to cold temperature for
18 days at the mean daily temperature of 11.8 Co, including 3-day
of low temperature at 8 Co between April 24-26 (LAAS, 2002).
Selection of 861 C418 plants with seedling cold tolerance
from 28 C418 BC2F2 populations 2002 (LAAS)
# of populations 28 2 26
BC2F2 CT donorsNon-CT
donors
Seedling Cold Tolerance (from NARES)
Range 1.4 – 19.3%
# of surviving plants
per population10.3%
The mean population size was 310, ranging from 196 – 465, the
recipient, C418 (japonica) was killed by the stress.
10 – 16% 0 – 3.0%
0.314%
# of surviving plants
per BC population10.3% 10.5%7.6%
Genetic background effects on the
performance of BC progenies
Teqing / Chipda NPT / Chipda
Donor Recurrent parent Donor Recurrent parent
ASD 16 10*** 0 Moroberekan 13 11
ASD18 59*** 0 54*** MR 77 31**** 0
B4122 37*** 2 1 Palung 2 33 36
Budda 75*** 11 Pokhreli 119**** 7 30***
IR64 Teqing NPT IR64 Teqing NPT
Donor and recipient effects on the number of BC2F2 plants
selected under lowland drought during the 2002 dry season
Budda 75*** 11 Pokhreli 119**** 7 30***
Chipda 47*** 0 85**** Pusa 15** 4
Chorofa 1 20*** Rasi 63*** 9
Dacca 6 20 19 Rusty Late 38**** 2 4
Dhan4 1 0 Sadajira 19 55**** 0
Doddi 81*** 2 Shwewartun 5* 0 6**
Gajale 61*** 22 SLG-1 26**** 0
Giza 14 29*** 4 SML242 6** 0 5*
IR64/SN89366 3.33 1.87 NPT/C418 0.00
Teqing/SN89366 6.67 3.75 IR64/CH448 9.33 4.14
NPT/SN89366 0.00 Teqing/CH448 7.33 3.25
IR64/Y134 7.33 3.45 NPT/CH448 0.00
Teqing/Y134 7.33 3.45 IR64/FR13A 7.67 3.64
NPT/Y134 0.00 Teqing/FR13A 6.67 3.17
IR64/BR24 8.00 3.61 NPT/FR13A 0.00
Cross Survival (%) Zvalue Cross Survival(%) Z value
Genetic background effects on the number of survival plants under submergence
in 33 BC4F2 populations from crosses between 3 RPs and 11 donors
Teqing/BR24 8.00 3.61 IR64/Madhukar 7.33 3.60
NPT/BR24 0.00 Teqing/Madhukar 6.00 2.95
IR64/Zihui 100 11.67 4.87 NPT/Madhukar 0.00
Teqing/Zihui 100 7.33 3.06 IR64/IR50 6.67 3.13
NPT/Zihui 100 0.00 Teqing/IR50 8.00 3.76
IR64/IR72 8.00 0.45 NPT/IR50 0.00
Teqing/IR72 8.00 0.45 IR64/Jhona349 5.00 2.73
NPT/IR72 7.00 Teqing/Jhona349 5.67 3.09
IR64/C418 7.33 3.19 NPT/Jhona349 0.00
Teqing/C418 10.00 4.35
IR64/SN89366 3.33 1.87 NPT/C418 0.00
Teqing/SN89366 6.67 3.75 IR64/CH448 9.33 4.14
NPT/SN89366 0.00 Teqing/CH448 7.33 3.25
IR64/Y134 7.33 3.45 NPT/CH448 0.00
Teqing/Y134 7.33 3.45 IR64/FR13A 7.67 3.64
NPT/Y134 0.00 Teqing/FR13A 6.67 3.17
IR64/BR24 8.00 3.61 NPT/FR13A 0.00
Cross Survival (%) Zvalue Cross Survival(%) Z value
Genetic background effects on the number of survival plants under submergence
in 33 BC4F2 populations from crosses between 3 RPs and 11 donors
Teqing/BR24 8.00 3.61 IR64/Madhukar 7.33 3.60
NPT/BR24 0.00 Teqing/Madhukar 6.00 2.95
IR64/Zihui 100 11.67 4.87 NPT/Madhukar 0.00
Teqing/Zihui 100 7.33 3.06 IR64/IR50 6.67 3.13
NPT/Zihui 100 0.00 Teqing/IR50 8.00 3.76
IR64/IR72 8.00 0.45 NPT/IR50 0.00
Teqing/IR72 8.00 0.45 IR64/Jhona349 5.00 2.73
NPT/IR72 7.00 Teqing/Jhona349 5.67 3.09
IR64/C418 7.33 3.19 NPT/Jhona349 0.00
Teqing/C418 10.00 4.35
Can we develop ILs with extreme
phenotypes for selected target
traits?
Selection for cold tolerance at the booting stageSelection for heat tolerance at the flowering stage
Seed set (%)Seed set (%) Spikelets per panicle
Donor 1N SI (%) 2
Mean 3 RangeN SI (%)
Mean 3 Range Mean 3 Range
Bg90-2 (I)41 9.11 63.3 d 50.3 - 86.5
25 6.25 41.3 abc 23.0–77.0 171.2 abc 124.0–253.1
X21 (I) 29 6.44 64.3 cd 50.6 - 87.19 2.25 38.1 abcd 19.5–50.0 192.5 ab 143.3–275.5
X22 (I) 28 6.22 65.6 bcd 50.7 - 87.3- - - - - -
Q5 (I) 31 6.89 71.1 abc 50.9 - 91.46 1.50 41.1 abc 19.9–75.4 160.4–274.2
Screening results of 11 BC2F4 backcross populations derived from crosses between a
japonica variety, Chaoyou 1 (the recurrent parent) and 11 donors for cold tolerance at the
booting stage and for heat tolerance at the flowering stage
Q5 (I) 31 6.89 71.1 abc 50.9 - 91.46 1.50 41.1 abc 19.9–75.4 160.4–274.2
Chhomrong (J) 24 5.33 51.4 - 87.817 4.25 37.7 abcd 19.3–65.5 172.9 abc 115.9–258.8
Doddi (I) 25 5.56 71.0 abc 50.2 - 90.0- - - - - -
Feng-Ai-Zhan (I) 44 9.78 52.2 - 98.512 3.00 31.3–70.1 180.7 abc 138.2–238.0
Shennong265 (J) 21 4.67 69.2 abcd 50.7 - 93.89 2.25 28.9 d 17.0–44.4 171.5 abc 112.0–216.7
Yuangeng7 (J) 41 9.11 71.1 abc 50.0 - 90.125 6.25 45.5 ab 23.9–65.6 83.2–255.4
OM997 (I) 21 4.67 72.1 ab 54.9 - 89.613 3.25 33.0 cd 17.0–48.9 171.9 abc 111.6–230.4
Cs94 (I) 19 4.22 64.2 cd 51.4 - 86.08 2.00 33.6 abcd 24.9–48.3 175.5 abc 121.4–280.4
Chaoyou (J) 324 6.55 24.8 e 19.0 - 30.0124 3.44
5.2 e 0.0–7.9 157.4 bc 127.4–178.6
2 N is the number of cold tolerant or heat tolerant BC plants selected from each population and SI = selection intensity.3 Different letters indicate the statistical significance in seed set at P < 0.05, based on the Duncan testing of ANOVA.
Table 6 Performances for AG of 11 promising BC4F3 lines and their donors
Recipient Donor Seedling height (cm) AG (%) Emerging at 10 d (%)
NPT Khazar 33.5 90.0* 20.0
NPT Khazar 32.5 95.0** 75.0**
NPT FR13A 37.7 95.0** 30.0
NPT TKM 9 37.7 100.0*** 95.0***
NPT TKM 9 36.2 100.0*** 60.0*
NPT TKM 9 37.9 100.0*** 95.0***
NPT Babaomi 34.9 100.0*** 50.0
NPT Babaomi 36.7 100.0*** 50.0
NPT OM1706 33.9 100.0*** 65.0*
NPT OM1706 36.1 100.0*** 80.0***
TKM 9 I 31.4 20.0 12.7
Khazar J 30.3 3.0 0.0
Babaomi I 26.3 5.0 0.0
Jiangxi-Si-Miao I 31.5 9.0 0.0
OM1706 I 29.1 18.0 2.0
IR64 I 26.5 20.0 2.0
NPT J 36.2 68.0 39.0
I = indica and J = japonica. Traits were measured at 21 d after seeding. All 10 ILs had significantly higher AG than the
recurrent parent, NPT at P < 0.001.
Drought tolerance 350 4687
BPH resistance 203 522
Salinity tolerance 203 1022
Target traits# of BC2F2populations
No. of selected
BC2F3 lines
Trait specific introgression lines developed
Anaerobic germination 130 368
Zinc deficiency 129 1211
Submergence tolerance 264 798
Grain quality 65 580
Other traits 375 12,000+
Total 20,000+
Summary of Selection Experiments
• Most donors contributed performance enhancing
alleles to their BC progenies regardless of their
performances;
• Appropriate screening (selection) is the key to
identify improved target traits in the BC identify improved target traits in the BC
progenies;
• More distantly related donors, particularly
landraces, tend to give more transgressive
segregations for abiotic tolerance in the BC
progenies.
� There are tremendous amounts of hidden genetic
diversity in the current rice germplasm
collections for genetic improvement of all target
traits we tried, which have not been exploited;
� Selection of parental lines for breeding based on
Conclusions
� Selection of parental lines for breeding based on
phenotype practiced by most breeders is a poor
way in exploiting novel genetic variation for
complex traits;
� Backcross breeding, effective selection (efficient
screening) combined with DNA markers are the
effective way to exploit this hidden diversity;
What are we going to do with
this large number of ILs?
1. Direct development of new cultivars;
2. As genetic stocks for discovery of DT alleles 2. As genetic stocks for discovery of DT alleles
or QTLs and functional genomics of DT;
3. As parents for development of superior rice
cultivars by QTL pyramiding
Progeny Testing of DT ILs Under Stress
(no irrigation after transplanting)
Check (C418)DT C418 ILs
Progeny Testing Under Stress
(no irrigation after transplanting)
Promising DT C418 ILs
2001-2002 DS BC2F4 progeny testing
IR64 (CK) DT IR64 ILsIR64 ILs for quality
Performance of two DT NPT ILs under severe stress
DT NPT ILs NPT CK
Performance of some promising salinity
tolerant IR64 ILs in the field condition in Iloilo
(EC 18 dSm-1 )
11/17, 2003
Performance of some promising salinity
tolerant IR64 ILs in the field condition in
Iloilo (EC 18 dSm-1 )
11/17, 2003
Promising varieties
developed in the BC
breeding programbreeding program
The Recurrent Parents
C418
(restorer)Liaojing454
Preliminary Yield Trials of Promising
DT/WUE ILs
30%
water
saving
70%
water
saving
50%
water
saving
Replicated Preliminary yield trial of DT/WUE ILs
(Shengyang/2006.9)
Completely
rainfed
Water
saving
70%
Water
saving
50%
Water
saving
30%
Promising DT/WUE
IL -HR95辽粳辽粳辽粳辽粳9号对照号对照号对照号对照
抗旱导入系的节水实验抗旱导入系的节水实验抗旱导入系的节水实验抗旱导入系的节水实验
30% water saving
10
15
20
25
Normal irrigation
Yield change over CK (%)
Yield performances of two promising DT/WUE
ILs in replicated yield trials under stress and
non-stress conditions (Shengyang/2006)
Completely rainfed
70% water saving
50% water saving
-5
0
5
10
HR94 HR95 Liaojing 9
(CK)
Yield change over CK (%)
in Liaojing 454background
10
15
20
25
Rainfed 70% 50% 30% Normal% change over CK
Yield potential and DT/WUE of DT ILs
-10
-5
0
5
10
HR354
(C418)
HR525
(C418)
HR9
(C418)
HR94
(LJ454)
HR95
(LJ454)
LJ9
(CK)
Promising DT/WUE FAZ ILs
Zhonghua 2Zhonghua 1
GSR material ST in Infanta
• GSR material
• material (572 lines)• material (572 lines)
• Other group’s material
2011-10-20
Lijun Meng
s
High EC Low EC
GS
R
NON-
GSRs
e
a
R GSR
NON GSR material
GSR material
HHZ HHZ HHZ HHZ 23-Sal8-DT1-ST1
HHZ 23-Sal24-DT1-STI HHZ 23-Sal8-DT1-ST1 HHZ 22-DT3-LI1-DT1HHZ 23-Sal24-DT1-STI
R1 R2
HHZ
CK
NSIC Rc 222
2011-10-7
HHZ 24-DT6-DT1-
DT1
HHZ 23-DT14-DT1-DT1IR 63307-4B-4-3
2011-10-7
HHZ 25-SAL9-Y3-ST1
Introgression Breeding for
improving 2 or more
complex traitscomplex traits
RP DonorsX
BC2F1
BC2F2
X
Screening under
severe drought
Selection for high yield
under normal condition
Screening under
severe salinity
Screening under
submergence
Promising ILs with more than one target traits to be
tested in multi-location yield trials in target Es
DT ILsST ILs HY ILsSUBT ILs
PT under severe
drought
PT for high yield under
normal condition
PT under severe
salinity
PT under
submergence
An example of the modified
introgression breeding procedure
used in GSR development
--
Development of HHZ ILs with one or
more improved target traits (yield, DT, ST,
SUBT and performance under low inputs)
Huang-Hua-Zhan (HHZ) is a mega rice variety
with high yield potential, superior quality
currently grown in ~2 million ha in South and
central China. It has wide adaptability (yielded
significantly higher than the best local checks) at
> 17 testing sites of Asia and Africa
Cote D’ivoir
Mali
Rwanda
Nigeria
Mozambique
Tanzania
Bangladesh
Indonesia
Pakista
n
Vietnam
Philip
pines
All
HHZ 2 1 3 1 3 1 2 1 1 1 1 17
Two batches of 16 populations with HHZ as the recipient and
16 donors from 9 different countries
Batch Pop. Donor Country of origin Gen.(10 DS)
1 HHZ5 OM1723 Vietnam (I) BC1F5
1 HHZ8 Phalguna India (I) BC1F5
1 HHZ9 IR50 IRRI (I) BC1F5
1 HHZ11 IR64 IRRI (I) BC1F5
1 HHZ12 Teqing China (I) BC1F5
1 HHZ15 PSB Rc66 Philippines (I) BC1F5
1 HHZ17 CDR22 India (I) BC1F51 HHZ17 CDR22 India (I) BC1F5
1 HHZ19 PSB Rc28 Philippines (I) BC1F5
2 HHZ1 Yue-Xiang-Zhan China (I) BC1F4
2 HHZ2 Khazar Iran (J) BC1F4
2 HHZ3 OM1706 Vietnam (I) BC1F4
2 HHZ6 IRAT352 CIAT (upland) BC1F4
2 HHZ10 Zhong 413 China (I) BC1F4
2 HHZ14 R644 China (I) BC1F4
2 HHZ16 IR58025B IRRI (I) BC1F4
2 HHZ18 Bg304 Sri Lanka (I) BC1F4
The Introgression Breeding Procedure
First batch of 8 HHZ BC1F2 populations (08WS)
DT screen SUB screen
3 SUBT plants
311 genotyped/progeny tested for all target traits
Random plants
109 DT plants
Yield traits
QTL/Allelic
diversity
discovery
for target
82 HY plants
ST screen
120 ST plants
06WS
08WS
09DS
1st round selection
12 RYT and 108 PYT under DT, low input, NC
Confirming genetic
networks for target
traits and their
genetic relationships
for target
traits
68 promising ILs
153 DT screen 171 SUB screen212 Yield 211 ST screen09DS
09WS 495 genotyped/progeny tested for all target traits
10DS
10WS/11DS68 replicated
yield trials
Used as parents for
designed QTL
pyramiding2 NCT
in 11WS3 Demo
2nd round selection
3rd round selection
The Introgression Breeding Procedure
Second batch of 8 HHZ BC1F2 populations (09WS)
DT screen SUB screen
21 SUBT plants
664 genotyped/progeny tested for all target traits
Random plants
210 DT plants
Yield traits
QTL/Allelic
diversity
discovery
for target
traits
119 HY plants
ST screen
314 ST plants
DT screen SUB screenYield under
NC & LIST screen
06WS
08WS
10DS
Confirming genetic
networks for target
traits and their
genetic relationships
traitsNC & LI
176 DT ILs 221 SUB ILs491 HY&FUE ILs 44 ST ILs
10WS 865 genotyped/progeny tested for all target traits
11DS
Promising ILs as parents for
designed QTL pyramiding
130 DT screen SUB screen232 yield
under NC&LIST screen
570 DT ILs SUB ILs305 HY&FUE ILs ST ILs
PYT11WSRYT &
DEMO
HHZ ILs with one or more improved target traits selected
from the 8 2nd BC populations
Improved traits Selected
ILs PYT NCYT
DT+LI 210 24 8
DT+ST 58 13 5
DT+SUBT 24 14
DT+HY 28 28 16
LI+ST 0 0 1
LI+HY 25 2
ST+SUBT 1 9ST+SUBT 1 9
ST+HY 33 33 8
SUBT+HY 7 2 1
DT+ST+SUBT 35 3 1
DT+ST+HY 154 9
DT+SUBT+HY 58 3
LI+ST+SUBT 20
LI+ST+HY 117
LI+SUBT+HY 36
ST+SUBT+HY 39
Total 845 140 40
Traits InstitutionNumber of
donorsILs selected
Drought toleranceCAAS
IRRI
8
15
180
978
CAAS 40 1200
Trait specific HHZ ILs developed in
CAAS and IRRI in 4 years
Salt toleranceCAAS
IRRI
40
15
1200
633
Tolerance to low inputs IRRI 250 350
Submergence tolerance IRRI 4 121
High yieldCAAS
IRRI
8
15
210
610
High yield under low
inputsIRRI 451 451
TotalCAAS
IRRI
40
15
1809
1260
Designation
Grain Yield (t/ha)Mean
over
seasons
% over
IR72
% over
NSICRc1
582010WS 2011DS
HHZ8-SAL6-SAL3-Y2 6.55ab 8.0ab 7.28 10.56 12.27
Performances of some high yield HHZ
ILs under irrigated conditions at IRRI
Mestizo7 (Hybrid) 5.68 bcde 8.7a 7.19 9.27 10.96
HHZ12-DT10-SAL1-DT1 6.75a 7.2 bcde 6.98 6.00 7.64
HHZ5-SAL10-DT1-DT1 6.14abcd 7.4 bcd 6.77 2.89 4.48
IR72 5.96abcde 7.2 cde 6.58 0.00 1.54
NSICRc158 5.86 bcde 7.1 cdef 6.48 -1.52 0.00
Reason: Higher HI, spikelets per panicle;panicles per sqm;total spikelets per sqm,CGR
Plot size: 30 sqm under SSNM
DT HHZ5-Sal14-Sal2-Y2 APO (check)
3000
4000
5000
6000
Viscosity, cP
60
80
100
120
Temperature
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
The HHZ ILs in RYT have diverse grain pasting properties
suitable for consumers with different taste preferences
-1000
0
1000
2000
0 100 200 300 400 500 600 700 800
Time, sec
Viscosity, cP
0
20
40
60
Temperature
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
AC=14.5-31.6%; GT= H-I-L; Protein=7.8-11.2%
BC2F2Bulk populations
Drought screen – DT ILsScreen for the
primary target trait
SalinityDisease and
insect resistances
Screen for
other traitsYield related
traits
QTL & QTL
networks for
Genotyping
Development of ILs with resistances to multiple
abiotic/biotic stresses
insect resistancestraits networks for
target and non-
target traits
Promising ILs with multiple
desirable traits (QTLs)
Parents for DQP Promising lines
Breeding by
DQP procedures
Yield trials at
multiple locations
IR# RP(%) Donor BPHR
(Score)
SBR
(LL, cm)
ST
(Score)
SUB
(%)
Yield/plant (g)
Mean CK%
IR82853-18 84.4 Type 3 3.2 3.0 25.7 68.6
IR82853-30 84.2 Type 3 3.0 3.8 27.2 77.9
IR82908-5 75.8 Bg300 3.0 4.0 17.9 17.1
IR82907-18 89.1 Babaomi 3.0 3.7 - -
IR82855-26 81.0 Binam 3.0 4.0 26.7 74.8
IR82861-10 80.5 RF13A 3.0 4.0 17.4 13.6
Development of IR64 ILs with multiple desirable traits
IR82861-10 80.5 RF13A 3.0 4.0 17.4 13.6
IR82865-2 89.5 Haonnong 3.0 3.0 15.9 3.9
IR82859-24 88.6 OM1723 3.0 4.0 20.7 35.3
IR82940-7 84.3 Basmati 3.0 100.0 - -
IR82863-2 79.5 Zihui 100 3.0 100.0 26.0 70.3
IR82855-1 91.7 Binam 3.0 3.0 22.1 44.7
IR82859-13 97.1 OM 1723 3.6 4.0 17.7 15.8
IR82865-24 89.5 Haonnong 3.0 4.0 88.9 34.5 125.8
IR82861-28 81.4 FR13A 3.0 4.0 100.0 - -
IR64(CK) 100.0 15.3 -
• When we are trying to improve
more than one complex trait, what
Question:
more than one complex trait, what
trait(s) should be selected first,
yield or abiotic/biotic stresses?
1: ST (57)
2: ST (49)
3: ST (56)
1: HY (26)
2: HY (28)
3: HY (29)
HHZ x Donors (1=IR64 , 2=AT354 , 3=C418)
F1 x HHZ
25 BC1F1 x HHZ
25 BC2F1
3 bulk BC2F2s (480)
X
1: DT (19)
2: DT (29)
3: DT (33)1st selection BC2F3s
2010 Beijing Summer
Population
development and
selection
2st selection1: DT (12)
2: DT (23)
3: DT (8)
3nd selection
3: ST (56)3: HY (29)
1: DT (0)
2: DT (0)
3: DT (1)
1: HY (2)
2: HY (1)
3: HY (2)
1: DT (0)
2: DT (0)
3: DT (2)
1: HY (0)
2: HY (2)
3: HY (1)
1: ST (25)
2: ST (28)
3: ST (29)
1: DT (3)
2: DT (4)
3: DT (2)
1: HY (3)
2: HY (5)
3: HY (2)
3: DT (33)1 selection
BC2F4s
BC2F5s
1: HY (0)
2: HY (2)
3: HY (3)
2010 Beijing Summer 2010 Hainan Winter 2010 Winter phytotron
2010 Hainan Winter 2010 Hainan Winter
Donor 1N T HD PH FGN TGW SNP SF PN GY
HHZ
(RP)
N Mean116.2±3.2 75.6±1.4
23.4±0.6 175.4±16.1 192.0±18.3 90.7±1.8 8.3±1.2 22.0±1.3
S Mean107.3±11.5 74..0±1.6
21.0±0.4 137.1±13.7 154.4±14.2 86.4±2.0 8.8±1.2 17.6±0.7
IR64 26
N
Mean111.8±5.1 75.6±4.4
22.5±3.0 171.9±47.6 197.3±49.3 86.8±5.5 7.9±1.6 22.7±6.6
Range101.0-111.0 66.3-78.9
15.2-26.0 106.7-255.8 136.3-272.4 74.4-93.8 6.2-10.6 12.8-32.6
S
Mean91.3±5.2 71.3±4.7
20.2±1.8 135.1±31.8 154.3±30.2 74.3±11.2 9.2±2.3 14.8±±±±5.2
Range78.0-99.5 65.0-77. 5
17.5-22.6 80.2-194. 9 98.1-203.6 49.4-91. 4.4-14.3 4.3-23.9
Performances of 83 HHZ BC2F5 introgression lines selected for high yield and their RP (HHZ)
under drought stress (S) and normal (N) conditions of Hainan in 2010 (1N: number of HY ILs, T:
treatment, N: normal condition, S: drought stress condition,)
78.0-99.5 65.0-77. 5
AT354 28
N
Mean107.1±7.3 72.5±2.3
20.3±1.0 184.8±28.8 231.0±31.4 79.9±4.3 10.2±1.6 27.6±5.5
Range98.5-110 69.2-74.8
19.0-22.0 127.8-217.8 166.7-273. 1 72.7-85.7 8.7-12.3 19.3-35.0
S
Mean90.1±7.0 65.7±3.9
18.6±1.2 119.1±19.7 145.3±26.4 63.3±13.4 9.6±1.9 10.9±±±±3.6
Range82.0-99.0 58.5-68.9
17.1-20.5 73.4-156.1 101.6-176.5 51.1-80.2 7.3-12.5 6.9-19.1
C418 29
N
Mean111.6±4.3 76.2±3.7
23.2±1.7 192.1±36.3 217.2±40.0 88.4±5.3 7.8±1.5 24.4±5.7
Range99.5-117.5 76.4-81.2
20.6-26.1 99.7-228. 7 142.4±270.6 70.4-92.5 4.6-11.7 13.9-40.4
S
Mean97.7±5.7 75.4±5.5
20.8±1.5 143.6±28.8 155.4±24.4 79.2±12.1 9.2±1.6 18.7±5.9
Range86.5-103 69.7-80.4
18.0-23.0 87.1-175.7 114.2-197.3 55.6-89.7 7.2-11.8 7.6-26.5
Donor T N1
HD PH GW FGW SNP SF PN GY
N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2 N1 N2
IR
N
26 0 5 0 2 1 4 1 1 1 0 0 6 0 0 2 0
AT354 16 0 9 0 1 0 12 0 1 1 0 0 12 3 0 1 0
C418 22 0 3 0 0 0 2 0 1 1 0 0 1 1 1 2 0
The numbers of ILs selected for high yield from the 3 populations that deviated
significantly HHZ for 9 measured traits evaluated under drought stress (S) and normal
(N) conditions of Hainan in 2010
C418 22 0 3 0 0 0 2 0 1 1 0 0 1 1 1 2 0
IR
S
26 0 25 2 5 0 5 0 5 0 1 0 6 0 2 0 2
AT354 16 0 16 0 15 0 6 0 9 0 0 0 13 1 0 0 7
C418 22 0 15 2 0 0 1 0 1 0 0 0 1 0 0 1 1
N1 is the total number of selections based on grain yield (GY) per plant in BC2F5 populations. N1 and N2 are the
numbers of the BC2F5 lines showing significantly higher or significantly lower than HHZ for the measured traits.
HD = heading date, PH = plant height, PL = panicle length, GW = 1000-grain weight, FGN = filled grain number
per panicle, SNP = spikelet number per panicle, SF = spikelet fertility, PN = panicle number per plant, GY =
grain yield.
L Donor Line#
Under the normal condition Under the drought stress condition
HD PH TGW FGN SNP SF PN GY HD PHTG
WFGN SNP SF PN GY
BJ
HHZ 115.3 - 23.1 172.8 189.0 91.4 7.6 23.1 - - - - - - - -
AT354
WT111 106.0 - 20.4 227.9 260.4 87.5 9.3 39.2 104.0 - 18.6 135.4 142.5 94.7 4.3 8.8
WT115 107.0 - 20.4 208.4 228.5 91.1 8.3 31.6 109.5 - 19.2 106.1 148.7 71.3 3.0 4.5
WT91 101.0 - 18.9 171.4 210.4 81.5 7.0 23.9 104.0 - 16.1 112.6 132.9 85.0 5.5 5.5
WT97 106.5 22.7 144.2 175.2 82.3 6.7 24.9 110.5 19.6 119.6 152.2 78.5 4.0 6.5
C418
WT183 103.5 - 21.0 251.7 300.7 83.7 8.3 33.5 113.5 - 17.5 123.9 151.2 81.9 5.3 5.9
WT184 107.0 - 20.9 187.7 204.7 91.7 8.3 31.6 113.0 - 17.8 117.6 149.6 78.6 5.3 6.0
WT185 103.5 - 21.8 165.6 189.9 87.2 10.7 32.5 115.5 - 19.2 141.7 159.0 89.1 4.0 8.2
Performances of some promising DT ILs under drought stress and normal
conditions in Beijing and Hainan, 2010
WT180 105.0 - 18.8 215.6 240.6 89.6 8.0 23.9 116.0 - 16.8 127.2 199.5 63.7 5.5 4.4
HN
HHZ 116.2 75.6 23.4 175.4 192 90.7 8.3 22.0 107.3 74 21.0 137.1 154.4 86.4 8.8 17.6
AT354
WT111 105.0 68.0 22.3 162.8 189.4 86.0 7.3 19.5 111.0 65.3 19.3 95.8 140.2 68.6 9.0 14.5
WT115 108.0 73.8 22.0 164 195.3 83.9 8.0 20.6 115.5 75.3 20.2 111.1 155.7 71.310.
416.4
WT91 111.0 80.7 20.9 181.8 232.1 78.3 11.5 38.3 119.5 73.5 17.9 123.4 144.9 85.811.
621.6
WT97 109.0 77.2 21.2 274.3 318.7 86.0 8.5 32.3 114.0 68.1 20.8 104.2 161.0 64.9 9.6 17.9
C418
WT183 114.5 76.5 23.8 133.8 145.0 92.3 6.7 22.5 125.0 74.6 20.8 92.9 111.5 83.2 9.9 23.9
WT184 114.0 74.4 24.7 156.3 176.7 88.5 8.6 29.3 125.0 75.6 20.8 123.6 140.6 89.0 6.8 15.5
WT185 113.0 73.3 24.5 174.6 192.2 91.1 9.8 31.3 121.0 72.8 21.4 119.3 132.3 90.2 9.4 26.9
WT180 115.0 81.2 24.5 188.4 200.8 93.8 8.8 36.2 125.0 85 21.9 150.4 183.6 82.1 8.7 26.9
� The selection order of DT(1) – HY(2) was
more effective than that of HY(1) – DT(2)
to combine both HY and DT;
� This result can not be adequately � This result can not be adequately
explained by the current quantitative
genetics theory. However, it does indicate
that it will make differences to determine
the correct order of target traits to be
selected when multiple complex traits are
to be improved.
What are we going to do with
this large number of ILs?
1. Direct development of new cultivars;
2. As genetic stocks for discovery of DT alleles 2. As genetic stocks for discovery of DT alleles
or QTLs and functional genomics of DT;
3. As parents for development of superior rice
cultivars by QTL pyramiding
Uses of ILs for
pyramiding genes/traits
from 2 or more donors to from 2 or more donors to
develop GSR varieties
IL1(HY, DT) x IL2(HY, DT)
F2
Screen
for DT
Screen
for ST
ST
IL3(HY, ST) x IL4(HY, ST)
Select for
HY and
random
Experimental design for simultaneous improvement of
DT, ST and yield potential by pyramiding
F2
Screen
for DT
Screen
for ST
Select for
HY and
random
DT
PDLs
ST
PDLs
Genotyping and progeny
testing for all target traits
Discovering genetic networks for HY, DT,
ST and their genetic overlap
HY, DT, ST
PDLs (PDL1)
DT
PDLs
ST
PDLs
Genotyping and progeny
testing for all target traits
HY, DT, ST
PDLs (PDL2)
Designed QTL pyramiding based on the genetic and
phenotypic information of parental ILs
IR64/BR24//IR64///IR64
BC2F2
IR64/Binam//IR64///IR64
BC2F2
Screening under drought
DT IR64/BR24 IL DT IR64/Binam ILXGenotyping
and QTL
identification
Genotyping
and QTL
identification identificationidentification
F1
F2
X
Screening under severe drought
Survival plants GenotypingProgeny testing
IL1 F2 IL2
Pyramiding F2 population screened under
severe lowland drought at the reproductive
stage (2002-03 DS)
P1 IL P2 IL F2 population
Cross Line Donor Line Donor Size No. SI (%)
II-1 DGI-74 BR24 DGI-187 Binam 318 90 28.3
II-2 DGI-21 STYH DGI-62 BR24 190 55 28.9
II-3 DGI-76 BR24 DGI-238 OM1723 248 55 22.2
An average of 25% of the progeny of the 9 F2populations survived the severe drought stress
II-4 DGI-21 STYH DGI-60 BR24 137 25 18.2
II-5 DGI-29 STYH DGI-353 Zihui100 154 30 19.5
II-6 DGI-75 BR24 DGI-187 Binam 154 30 19.5
II-7 DGI-142 Type3 DGI-373 HAN 255 70 27.5
II-8 DGI-146 Type3 DGI-353 Zihui100 135 70 51.9
II-9 DGI-150 Type3 DGI-374 HAN 219 30 13.7
Total 1810 455 25.1
Yield performances of 90 (3 major group genotypes)
PLs from pyramiding population 1 in 2004 dry-season
Control Terminal stress
2.0
4.0
6.0
8.0
0.4
0.8
1.2
1.6
2.0
GG1 (X = 109±±±±20, 66%)
GG2 (X = 247±±±±35, 149%)
GG4 (X = 117±±±±18, 70%)
GG3 (X = 140±±±±33, 84%)
GG1 (X = 35±±±±8, 361%)
GG2 (X = 33±±±±12, 344%)
GG4 (X = 34±±±±8, 373%)
GG3 (X = 35±±±±13, 364%)
0 0
0.4
GG1 GG2 GG3GG4 IR64 GG1 GG2 GG3GG4 IR64
IR64 (X=166±±±±10, 100%) IR64 (X=9.7±±±±5, 100%)
Yield
Source DF MS F P > F R2 (%)
Stress 1 824575.5 820.64 0.0001 23.2
Group 5 90892.7 90.46 0.0001 12.8
Group(Line) 83 1778.9 1.77 0.0002 4.1
Stress*Group 5 97151.2 96.69 0.0001 13.7
ANOVA Result for Yield of 2004 Dry Season
Stress*Group 5 97151.2 96.69 0.0001 13.7
Stress*Group(Line) 83 1576.9 1.57 0.0029 3.7
Stress
Group 5 312.9 1.17 0.3255 2.0
Group(Line) 83 374.6 1.4 0.0332 40.0
Control
Group 5 187440.6 113.55 0.0001 62.3
Group(Line) 83 3086.6 1.87 0.0003 17.0
Control Stress
100
200
300
400
500
40
60
80
100
120
140
160
Yield performances of the 4 group genotypes under the rainfed
upland stress and non-stress conditions in 2004 wet-season
0
100
0
20
40
GG1 GG2 GG3 GG4 IR64
GG1 (X=50±±±±22, 1111%)GG2 (X=44±±±±24, 978%)GG4 (X=62±±±±31, 1378%)GG3 (X=55±±±±19, 1222%)
GG1 GG2 GG3 GG4 IR64
GG1 (X=124±±±±20, 51%)GG2 (X=310±±±±34, 129%)GG4 (X=122±±±±44, 51%)GG3 (X=212±±±±37, 88%)IR64 (X=241±±±±27, 100%) IR64 (X=4.5±±±±8, 100%)
ANOVA Results for Yield of 2004 Wet Season
12.6 12.6 12.6 12.6 0.0001174.6174.6174.6174.6259596.4 3Stress*Group
4.1 0.00012.063057.4 83Group(Line)
10.7 10.7 10.7 10.7 0.0001147.8147.8147.8147.8219664.33Group
40.4 40.4 40.4 40.4 0.00011676.01676.01676.01676.02491548.91Stress
R2(%)P > FFMSDFSource
YIELD
21.8 21.8 21.8 21.8 0.00013.525591.6 83Group(Line)
65.3 65.3 65.3 65.3 0.0001292.2292.2292.2292.2464372.9 3Group
Control
36.3 36.3 36.3 36.3 0.05271.341773.4 83Group(Line)
6.9 0.00114.264.264.264.265626.6 3Group
Stress
5.8 0.00012.94307.3 83Stress*Group(Line)
12.6 12.6 12.6 12.6 0.0001174.6174.6174.6174.6259596.4 3Stress*Group
2.0
4.0
6.0
8.0
ControlStress
Yield performance of the 4 group genotypes under
mild stress in 2005 dry-season
GG2 GG4 GG3 CK0
2.0
GG1 GG2 GG4 GG3 CKGG1
GG1 (X=237±±±±58, 149%)GG2 (X=313±±±±46, 197%)GG4 (X=227±±±±47, 143%)GG3 (X=249±±±±50, 157%)IR64 (X=159±±±±40, 100%)
GG1 (X=157±±±±29, 75%)GG2 (X=247±±±±33, 119%)GG4 (X=173±±±±38, 83%)GG3 (X=164±±±±28, 79%)IR64 (X=208±±±±57, 100%)
151%
127%
152%
131%
76%
� Strong selection under severe drought resulted in
a few major group genotypes that have
significantly improved DT, and showed highly
Summarized Results from 1st round
pyramiding breeding
significantly improved DT, and showed highly
significant differences in multiple phenotypes
under the non-stress conditions;
� We have identified a group genotype that have significantly improved yield potential and WUE/DT.
1. Large numbers of loci are involved in DT of rice, and these DT loci appear to be under strong epigenetic control and tend to form complex genetic networks with clear hierarchy;
2. Strong selection under severe drought resulted in a few major group genotypes that have significantly improved DT, and showed highly significant differences in multiple phenotypes under the non-stress conditions;
Summary
non-stress conditions;
3. Group 4 loci were associated with severe yield penalty by 30-50%;
4. Group 5 loci were associated with improved yield potential (faster growth rate and greater sink capacity)
5. We have identified promising rice lines with group genotype (1, 2, 3, and 5) that have significantly improved yield potential and WUE/DT. These lines are being tested in the multi-location yield trials in South/Southeast Asia.
• The overall level of DT in rice appears to depend more
on the combination of QTLs and less on the absolute
number of QTLs that remains to be elucidated; and
Summarized results
• High level of DT at the reproductive stage in rice is not
necessarily associated with a penalty in yield potential
under normal irrigated conditions. Thus, it is possible to
combine high level of DT (at least for DT at the
reproductive stage) and high yield potential.
Selection intensity of the 2nd round pyramiding F2populations
P1 PLs P2 PLs F2
Cross Line Origin Line Origin N Drought SI%
III-1 DK47 II-1 DK109 II-2 420 56 13.3
III-2 DK47 II-1 DK148 II-2 428 60 14.0
III-3 DK47 II-1 DK158 II-2 439 97 22.1
III-4 DK47 II-1 DK356 II-3 413 72 17.4
III-5 DK47 II-1 DK388 II-3 425 49 11.5
II-1 II-2 24 32.0 III-6 DK39 II-1 DK148 II-2 75 24 32.0
III-7 DK39 II-1 DK158 II-2 422 70 16.6
III-8 DK39 II-1 DK356 II-3 269 55 20.4
III-9 DK39 II-1 DK388 II-3 435 20 4.6
III-10 DK65 II-1 DK109 II-2 382 50 13.1
III-11 DK65 II-1 DK148 II-2 305 40 13.1
III-12 DK65 II-1 DK158 II-2 403 51 12.7
III-13 DK65 II-1 DK356 II-3 112 20 17.9
III-14 DK65 II-1 DK388 II-3 220 3 1.4
Total 4748 667 15.0
Selection for HY and DT in 14 2nd DQP F2 populations from
crosses bet. 8 IR64 PDLs each with multiple DT QTLs from 2
donors (05-06 DS, IRRI)
Donor1 Donor2 Donor3 Donor4Non-stress Stress
Pop. size Sel. for yield Pop. size Sel. for DT
STYH BR24 BR24 Binam 127 8 (26.7) 75 24 (6.2)
STYH BR24 BR24 Binam 450 21 (27.2) 422 70 (7.4)
STYH BR24 BR24 OM1723 296 25 (26.4) 269 55 (6.6)
STYH BR24 BR24 OM1723 405 20 (22.3) 435 20 (4.5)
STYH BR24 BR24 Binam 450 30 (30.3) 420 56 (9.9)
STYH BR24 BR24 Binam 435 17 (28.6) 428 60 (12.6)
STYH BR24 BR24 Binam 450 18 (32.0) 439 97 (11.3)
STYH BR24 BR24 OM1723 435 31 (26.2) 413 72 (9.4)
STYH BR24 BR24 OM1723 419 17 (22.0) 425 49 (5.4)
STYH BR24 BR24 Binam 435 14 (30.6) 382 50 (8.2)
STYH BR24 BR24 Binam 241 8 (31.4) 305 40 (7.0)
STYH BR24 BR24 Binam 443 21 (23.5) 403 51 (6.7)
STYH BR24 BR24 OM1723 120 9 (29.3) 112 20 (10.1)
STYH BR24 BR24 OM1723 315 15 (31.0) 220 3 (4.5)
Average 358.6 18.1 (27.7) 339.1 47.6 (7.9)
Field screening of the 2nd round DQP F2populations under severe lowland stress
(2005-2006 dry season)
F2 populationMale
PDL1
Female
PDL2
IR64
F2 population
Parental ILs and IR64
Field screening of the 2nd round DQP F2populations under severe upland stress
(2005-2006 dry season)
IR64DK158DK47
Population
Controlled irrigated condition
Field screening of the 2nd round DQP F2 populations
under severe upland stress (05-06 dry season)
PopulationDK47 DK158 IR64
Lowland stress
DK47 DK109 IR64
Population
Controlled irrigated condition
Field screening of the 2nd round DQP F2 populations
under severe upland stress (05-06 dry season)
DK47 DK109 IR64Population
DK47 DK109 IR64
Lowland stress
Uses of ILs for
molecular recurrent
selection (MRS)
Molecular Recurrent Selection (MARS) Systems for Improving
Multiple Complex Traits for Different Target Environments Based
on Trait-Specific ILs and Dominant CMS (under the way)
Composition of the MRS populations: 50+ ILs/PLs carrying favorable QTL alleles from
different donors plus the DCMS line in the same genetic backgrounds
HHZ MRS population MRS population in a New GB
Bulk harvest seeds
from CMS plants to
be screened for
target traits
Bulk harvest seeds
from CMS plants to
be screened for
target traits
Normal plants
CMS plants
Ovals or boxes of different colors represent different ILs carrying genes/QTLs for different target traits
Bulk harvest seeds
from CMS plants to
be screened for
target traits
Selected plants enter
the progeny testing,
genotyping and next
round of RS
Bulk harvest seeds
from CMS plants to
be screened for
target traits
Selected plants enter
the progeny testing,
genotyping and next
round of RS
On-going MRS in phase II of the GSR project
Each MRS population consisting of many ILs/PLs of the same elite GB
50% fertile plants
Flood prone
Rainfed lowland
Each MRS population (remove plants with undesirable traits)
Irrigated(YP)
Rainfed upland
Biotic stresses
Continued introgression breeding/DQP
50% DMS plants
New MRS for
next round
Genotyping for gene/QTL
discovery, confirmation and
monitoring trait improvement
New lines for PYT
Improved lines for PT
New ILs/PLs
RYT and NCT under different target Es
Farmers in dif. target Es
Continuation
of MRS
Breeding Procedure of Molecular Recurrent Selection (MRS)
50% fertile plants
Screen for biotic stress resistances
Random mating
Screening abiotic stress tolerances
Multiple MRS populations
Yield traits
Screen quality traits Superior
ILs/PLs
Continued IB and
pyramiding50% MS plants
Genome selection and trait design and
improvement based on genetic information
of the parents of MRS populationsMaterial platform for
large scale MB
Technology for pyramiding multiple
genes/traits and quick progeny
fixation based on combined genome
and phenotypic selection
NS
NS
PS
Random mating
population for
next round MRS
SNP genotyping、、、、gene/QTL
discovery、、、、allelic mining and
confirmation, trait design and
improvement
Preliminary yield trial of promising lines
Cross progeny testing for multiple traits and
confirmation
Multi-location yield trials of promising lines
Demonstration & PVS in the target environments
Continued
MRS
Genome selection and trait design and
improvement based on genetic information
of the parents of MRS populations
Genome sequence information platform of the rice core collection
Technology for pyramiding multiple
genes/traits and quick progeny
fixation based on combined genome
and phenotypic selection
PS = positive
selection
NS = negative
selection
PS
NS
Conclusions
• There are tremendous amounts of hidden genetic
diversity for almost all complex phenotypes in the
primary gene pool, and selection of parental lines
based on phenotype practiced by most breeders is a
poor way to exploit this hidden diversity.Development of rice cultivarsn and
discovery of genes/QTLs for complex
• The genetic network for complex phenotypes are
very complex - large number of loci and multiple
functional alleles at most of the loci.
• Backcross breeding, effective selection (screening)
combined with DNA markers are the effective way
to discover and exploit this hidden diversity.
discovery of genes/QTLs for complex
phenotypes can be and should be
integrated.
Thank you for your attention!