Chapter 7
BREEDING FOR HETEROSIS
杂种优势育种
BY
Niu Yingze
（牛应泽）
Dept,of Plant Breeding and Seed Engineering
§ 1 Utilization of Heterosis in Plant
Production
杂种优势在生产上的利用
1,What is Plant Heterosis? p,117
2,Discovery and History of Heterosis
Animals Horse x donkey,1400 years ago,China
Plants
The Emergent Period
Kolreuter(1761-1766),Hybrid Tobacco,
Darwin(1860’s), Hybrid maize vigor
Mendel(1860’s), Pea,hybrid vigor
Maize,Beal(1876),Varietal maize hybrids
The Foundation Period
?Maize,Shull(1905-09); East(1908),Inbred lines - Single cross
Shull (1914),The term HETEROSIS for hybrid vigor
Jones(1918 ),Double cross
H,A,Wallace,Pioneer Hi-Bred Corn Conpany
The Development Period
?Maize,1920-1960’s Double cross/Three-way cross/Single cross
?Sorghum,Three-line hybrid; Use of cms-System,1950’s
?Rice,Heterotic Hybrid rice,three-line system
The Father Yuan Longping,1964-1972
?Rape,Hybrid Rapeseed,three-line types;
The Father Li Dianrong,The 1st hybrid rape variety
The Pioneer Fu Tingdong,The Polima cms
?Other Crops,More and more
2,The Concept of Heterosis
? Hybrid heterosis and Hybrid vigor
? Types of Heterosis,1) vegetative,2) productive
3)adaptive
? Measurement of Heterosis p,118-119
(1) Mid-parent heterosis
(2) Over-parent heterosis
(3) Over-standard (Over check heterosis)
(4) Heterotic Index
3,The Characteristics of Heterotic
Performance in Plants
(1) Multiple-character Phenomenon
(2) Related to Parental Genetic Difference
(3) Related to Parental Homozygosity
(4) Environment Dependent
(5) Depression of Heterosis in F2 and later generations
4,The Fixation of Heterosis
P.120
§ 2 Genetic Basis of Heterosis
杂种优势的遗传基础
1,The Dominance Hypothesis
P1 AABBccddEE x aabbCCDDee P2
AaBbCcDdEe
F1
10+10+5+5+10=40 5+5+10+10+5=35
10+10+10+10+10=50
F1 > P1,P2
2,The Over-dominance Hypothesis
P1 a1a1b1b1c1c1d1d1e1e1 x a2a2b2b2c2c2d2d2e2e2 P2
a1a2b1b2c1c2d1d2e1e2
F1
(12) (10)
(20)
where,a1a2 > a1a1,a2a2; b1b2 > b1b1,b2b2 …
§ 3 Reproduction Modes of Crops and The
Exploitation of Heterosis 杂种优势的遗传基础
1,The Basic Principles of Exploitation
? Easy Manipulation
? Low Cost (of seed production)
? Obvious Heterosis
2,Reproduction modes and the Exploitation
? Self pollinated and often cross pollinated plants
Intervarietal hybrid; Male Sterility (cms,nms)
? Cross pollinated plants (Manual emasculation)
? Vegetatively propagated plants (Fixing heterosis)
§ 4 General Procedure for Hybrid Breeding
杂种优势的遗传基础
1,Types of Hybrids (or Hybrid Varieties)
? Inter varietal Hybrid 品种间杂种 (Chemical way,wheat)
? Inter inbred line Hybrid 自交系间杂交种 (Maize)
? Inter self-incompatable line Hybrid 自交不亲和系杂交种
? Inter specific Hybrid 种间杂种 (Cotton)
? Inter cytoplasmic vs nucleate Hybrid 核质杂种
? Male sterility Hybrid 雄性不育杂种 (Rice)
Three-line Hybrid
Two-line Hybrid
One-line Hybrid
2,Breeding of Parent Lines
? Breeding for inbred line in maize,Continuous self-
breeding
Inbred Line is the offspring derived from a superior
single plant after a series of artificial inbreeding (or self-
breeding) and selection,An inbred line is a homozygous
line,a pure line,a uniform line and a stable line,It can be
reproduced faithfully year after year,It is essential for
continuous production of hybrid seed of the same genetic
constitution over years,It also ensures extreme uniformity
in the hybrids,
3,Test of Combining Ability
(1)Combining Ability (GCA,SCA) (see p,89)
GCA --- Mean value of a line over the Grand mean of all
the crosses.,
GCA = Mean of Line A – Grand mean of all crosses
SCA --- Performance of a specific cross(i.e,A x B)
The Deviation of the following equation,
SCA= (Value of A x B) – Grand mean – GCAA - GCAB
(2) Testing of GCA (Top Cross,顶交法 )
Inbred line x Complex population (OP population)
(3) Testing of SCA (individual cross 单交法 )
Line A x Line B; Line A x Line C; Line B x Line C
(4) Combined Test (Diallel Test 双列杂交 ),
For both GCA,SCA,
Line A x Line B Line B x Line C
Line A x Line C Line B x Line D
Line A x Line D Line B x Line E
Line A x Line E Line C x Line D
… … …
(1) Single cross hybrid (Two inbred lines)
(2) Double cross hybrid (Four inbred lines)
(3) Three-way cross hybrid (Tree inbred lines)
(4) Synthetic hybrid (Over 8 inbred lines)
4,Kinds of Inbred line Hybrids
5,Pathways (Ways ) of Heterosis Exploitation
杂种优势利用的途径
The ways refer to the systems applied in seed
production
? Fertility Regulating Mechanism in Plant
(1) Manual or mechanical control
(2) Genetical control (Incompatibility; MS)
(3) Chemical control
? Ways of Hybrid Seed Production
(1) Manual or mechanical emasculation (maize,tomato,
tobacco) 人工去雄
(2) Use of marker characters (cotton) 利用标志性状
(3) Chemical hybridizing agents (wheat) 化学杀雄
(4) Using self-incompatibility (crucifers) 利用自交不亲和
性
(5) Using male sterility (rice,rape,cotton,sorghum,
maize …) 利用雄性不育性
(6) Use of female plant line (in spinach,菠菜 )
Full female lines; High-degree female line(maintainer)
Perfect lines
Full female x perfect -----F1 hybrid
(7) Use of Male plant line (in asparagus，芦笋 )
XX line ---female line
XY line --- male line
YY line --- Super male line
XX x YY ----- XY (F1 hybrid,Male)
(8) Use of female line (in cucumber，黄瓜 )
Full female line
Normal line (female flower + male flower)
Full female line x Normal line ---- F1 hybrid
§ 5 Exploitation of Male Sterility for Heterosis
Breeding 雄性不育性在杂种优势利用中的应用
1,The Significance
? Labor saving,time saving,cost saving
? Effective parental control
? More reliable quality
2,Types of Male Sterility
? Cytoplasmic Male Sterility/CMS
? Nucleate Male Sterility/NMS
（ Genic Male Sterility/GMS)
? Cytoplasmic-nucleate Male Sterility
C(N)MS/CMS
S
msms
S
msms
×
√
√√
3,Application of Cytoplasmic-nucleate Male
Sterility (CMS)
(1) The three lines
A Line – Male sterile line
B Line - Maintainer line
R Line – Restorer line
（ 2） Breeding of Male Sterile Line and
Maintainer Line
① Source of Male Sterility,
a,Natural discovery
b,Distant hybridization (Interspecific,intergeneric,Inter-
distant ecological type crosses)
② Breeding of MS lines and B lines (Nucleus substitution 核置
换法）
a,Distant Cross + Backcross
b,Testcross + Backcross (Transformation method,Fig.7-2)
（ 4-5 backcrosses)
（ 3） Breeding of Restorer Lines
a,Testcrosses
A line × Normal lines ( a series)
b,Cross breeding
R × R R
R × Lines R
A × R R
(4) Three-line Seed Production System
不育系繁殖区
（含保持系繁殖）
（ Isolation 1） （ Isolation 2）
不育系
S(msms)
保持系
F(msms)
保持系
F(msms)
不育系
S(msms)
×
?
小部分 大部分
不育系
S(msms)
恢复系
S(MsMs)
F(MsMs
杂交种
S(Msms)
×
恢复系
S(MsMs)
F(MsMs
大田推广
?
杂交制种区
（含恢复系繁殖）
4,Application of GMS
(1) Source of GMS
Mutations
Transfer from existing GMS lines (Backcrossing)
(2) Types of GMS
A,Recessive gms
msms (sterile) MsMs/Msms (Fertile)
No B-lines
B,Dominant gms
msms (Fertile) MsMs/Msms (sterile)
No R-lines
(3) Seed Production of Recessive gms system
msms x MsMs Msms
A R R(F1 hybrid)
msms x Msms 1/2Msms+1/2msms
A B plant R × A
Self-reproduction
Seed production of Recessive GMS Lines
A line zone
50% msms
50%Msms
（ Double use line)
核不育两用系
R line zone
MSMS
×
A line zone
50% msms
50%Msms
（ Double use line)
核不育两用系
ISOLATION I ISOLATION II
MS line F1 hybrid
（ 4）双基因显性核不育 （含一个显性不育抑
制基因）的利用,
? 基因型 (RfRf 显性上位性基因）
不育系 MsMsrfrf (纯合两型系 )
Msmsrfrf (杂合两型系 )
恢复系 MsMsRfRf
msmsRfRf
半恢复系 _ _ Rfrf
临时保持系 msmsrfrf
? 表现型 Ms_ Rf_ 可育
MsmsRf 可育
Ms_ rfrf 不育
msmsrfrf 可育（为临保系）
? 双基因显性核不育系的临时保持
MsMsrfrf x msmsrfrf
（ 纯合两型系 ） （临保系）
Msmsrfrf
（杂合两型系,100%雄性不育）
（ 2） 纯合两型系的繁殖
MsMsrfrf x MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
（四）核不育系的利用
1、用于杂交制种
（ 1）隐性核不育 ——―二系法,
（ 2）显性核不育 ——―三系法,
（ 3）采用染色体工程
·大麦 平衡三级三体
·玉米 缺失易位双杂合体
,小麦 X,Y,Z体系
（ 4）光敏核不育 制种
2、用于育种手段
·群体改良 —小麦太谷核不育利用
·远缘杂交等 (不需去雄 )
1,Self-incompatibility p.137
§ 6 Breeding and Utilization of Self-incompatible Lines
for Heterosis 自交不亲和系的利用
Self Incompatible Lines,
Perfect flowers
Normal gynaecium (Viable stigma)
Normal androecium (Viable pollens)
Self-pollination incompatible
Use for Heterosis,Hybrid crosses
Multiplication Problems,Selfing for pure lines
Multiplication Methods,
（ 1） Early pollination
(2) Spraying salt solution,3-8%
(3) Steel Brush treatment
(4) Chemical treatment
2,Multiplication of self-incompatible lines
3,Seed Production in the Self-incompatible
System 自交不亲和杂种的种子生产
SI
1
S1S1
SI
2
S2S2
SI
3
S3S3
SI
4
S4S4
SINGLE CROSS A SINGLE CROSS B
DOUBLE CROSS
SI
5
S5S5
3-WAY CROSS
Till Next Chapter
BREEDING FOR HETEROSIS
杂种优势育种
BY
Niu Yingze
（牛应泽）
Dept,of Plant Breeding and Seed Engineering
§ 1 Utilization of Heterosis in Plant
Production
杂种优势在生产上的利用
1,What is Plant Heterosis? p,117
2,Discovery and History of Heterosis
Animals Horse x donkey,1400 years ago,China
Plants
The Emergent Period
Kolreuter(1761-1766),Hybrid Tobacco,
Darwin(1860’s), Hybrid maize vigor
Mendel(1860’s), Pea,hybrid vigor
Maize,Beal(1876),Varietal maize hybrids
The Foundation Period
?Maize,Shull(1905-09); East(1908),Inbred lines - Single cross
Shull (1914),The term HETEROSIS for hybrid vigor
Jones(1918 ),Double cross
H,A,Wallace,Pioneer Hi-Bred Corn Conpany
The Development Period
?Maize,1920-1960’s Double cross/Three-way cross/Single cross
?Sorghum,Three-line hybrid; Use of cms-System,1950’s
?Rice,Heterotic Hybrid rice,three-line system
The Father Yuan Longping,1964-1972
?Rape,Hybrid Rapeseed,three-line types;
The Father Li Dianrong,The 1st hybrid rape variety
The Pioneer Fu Tingdong,The Polima cms
?Other Crops,More and more
2,The Concept of Heterosis
? Hybrid heterosis and Hybrid vigor
? Types of Heterosis,1) vegetative,2) productive
3)adaptive
? Measurement of Heterosis p,118-119
(1) Mid-parent heterosis
(2) Over-parent heterosis
(3) Over-standard (Over check heterosis)
(4) Heterotic Index
3,The Characteristics of Heterotic
Performance in Plants
(1) Multiple-character Phenomenon
(2) Related to Parental Genetic Difference
(3) Related to Parental Homozygosity
(4) Environment Dependent
(5) Depression of Heterosis in F2 and later generations
4,The Fixation of Heterosis
P.120
§ 2 Genetic Basis of Heterosis
杂种优势的遗传基础
1,The Dominance Hypothesis
P1 AABBccddEE x aabbCCDDee P2
AaBbCcDdEe
F1
10+10+5+5+10=40 5+5+10+10+5=35
10+10+10+10+10=50
F1 > P1,P2
2,The Over-dominance Hypothesis
P1 a1a1b1b1c1c1d1d1e1e1 x a2a2b2b2c2c2d2d2e2e2 P2
a1a2b1b2c1c2d1d2e1e2
F1
(12) (10)
(20)
where,a1a2 > a1a1,a2a2; b1b2 > b1b1,b2b2 …
§ 3 Reproduction Modes of Crops and The
Exploitation of Heterosis 杂种优势的遗传基础
1,The Basic Principles of Exploitation
? Easy Manipulation
? Low Cost (of seed production)
? Obvious Heterosis
2,Reproduction modes and the Exploitation
? Self pollinated and often cross pollinated plants
Intervarietal hybrid; Male Sterility (cms,nms)
? Cross pollinated plants (Manual emasculation)
? Vegetatively propagated plants (Fixing heterosis)
§ 4 General Procedure for Hybrid Breeding
杂种优势的遗传基础
1,Types of Hybrids (or Hybrid Varieties)
? Inter varietal Hybrid 品种间杂种 (Chemical way,wheat)
? Inter inbred line Hybrid 自交系间杂交种 (Maize)
? Inter self-incompatable line Hybrid 自交不亲和系杂交种
? Inter specific Hybrid 种间杂种 (Cotton)
? Inter cytoplasmic vs nucleate Hybrid 核质杂种
? Male sterility Hybrid 雄性不育杂种 (Rice)
Three-line Hybrid
Two-line Hybrid
One-line Hybrid
2,Breeding of Parent Lines
? Breeding for inbred line in maize,Continuous self-
breeding
Inbred Line is the offspring derived from a superior
single plant after a series of artificial inbreeding (or self-
breeding) and selection,An inbred line is a homozygous
line,a pure line,a uniform line and a stable line,It can be
reproduced faithfully year after year,It is essential for
continuous production of hybrid seed of the same genetic
constitution over years,It also ensures extreme uniformity
in the hybrids,
3,Test of Combining Ability
(1)Combining Ability (GCA,SCA) (see p,89)
GCA --- Mean value of a line over the Grand mean of all
the crosses.,
GCA = Mean of Line A – Grand mean of all crosses
SCA --- Performance of a specific cross(i.e,A x B)
The Deviation of the following equation,
SCA= (Value of A x B) – Grand mean – GCAA - GCAB
(2) Testing of GCA (Top Cross,顶交法 )
Inbred line x Complex population (OP population)
(3) Testing of SCA (individual cross 单交法 )
Line A x Line B; Line A x Line C; Line B x Line C
(4) Combined Test (Diallel Test 双列杂交 ),
For both GCA,SCA,
Line A x Line B Line B x Line C
Line A x Line C Line B x Line D
Line A x Line D Line B x Line E
Line A x Line E Line C x Line D
… … …
(1) Single cross hybrid (Two inbred lines)
(2) Double cross hybrid (Four inbred lines)
(3) Three-way cross hybrid (Tree inbred lines)
(4) Synthetic hybrid (Over 8 inbred lines)
4,Kinds of Inbred line Hybrids
5,Pathways (Ways ) of Heterosis Exploitation
杂种优势利用的途径
The ways refer to the systems applied in seed
production
? Fertility Regulating Mechanism in Plant
(1) Manual or mechanical control
(2) Genetical control (Incompatibility; MS)
(3) Chemical control
? Ways of Hybrid Seed Production
(1) Manual or mechanical emasculation (maize,tomato,
tobacco) 人工去雄
(2) Use of marker characters (cotton) 利用标志性状
(3) Chemical hybridizing agents (wheat) 化学杀雄
(4) Using self-incompatibility (crucifers) 利用自交不亲和
性
(5) Using male sterility (rice,rape,cotton,sorghum,
maize …) 利用雄性不育性
(6) Use of female plant line (in spinach,菠菜 )
Full female lines; High-degree female line(maintainer)
Perfect lines
Full female x perfect -----F1 hybrid
(7) Use of Male plant line (in asparagus，芦笋 )
XX line ---female line
XY line --- male line
YY line --- Super male line
XX x YY ----- XY (F1 hybrid,Male)
(8) Use of female line (in cucumber，黄瓜 )
Full female line
Normal line (female flower + male flower)
Full female line x Normal line ---- F1 hybrid
§ 5 Exploitation of Male Sterility for Heterosis
Breeding 雄性不育性在杂种优势利用中的应用
1,The Significance
? Labor saving,time saving,cost saving
? Effective parental control
? More reliable quality
2,Types of Male Sterility
? Cytoplasmic Male Sterility/CMS
? Nucleate Male Sterility/NMS
（ Genic Male Sterility/GMS)
? Cytoplasmic-nucleate Male Sterility
C(N)MS/CMS
S
msms
S
msms
×
√
√√
3,Application of Cytoplasmic-nucleate Male
Sterility (CMS)
(1) The three lines
A Line – Male sterile line
B Line - Maintainer line
R Line – Restorer line
（ 2） Breeding of Male Sterile Line and
Maintainer Line
① Source of Male Sterility,
a,Natural discovery
b,Distant hybridization (Interspecific,intergeneric,Inter-
distant ecological type crosses)
② Breeding of MS lines and B lines (Nucleus substitution 核置
换法）
a,Distant Cross + Backcross
b,Testcross + Backcross (Transformation method,Fig.7-2)
（ 4-5 backcrosses)
（ 3） Breeding of Restorer Lines
a,Testcrosses
A line × Normal lines ( a series)
b,Cross breeding
R × R R
R × Lines R
A × R R
(4) Three-line Seed Production System
不育系繁殖区
（含保持系繁殖）
（ Isolation 1） （ Isolation 2）
不育系
S(msms)
保持系
F(msms)
保持系
F(msms)
不育系
S(msms)
×
?
小部分 大部分
不育系
S(msms)
恢复系
S(MsMs)
F(MsMs
杂交种
S(Msms)
×
恢复系
S(MsMs)
F(MsMs
大田推广
?
杂交制种区
（含恢复系繁殖）
4,Application of GMS
(1) Source of GMS
Mutations
Transfer from existing GMS lines (Backcrossing)
(2) Types of GMS
A,Recessive gms
msms (sterile) MsMs/Msms (Fertile)
No B-lines
B,Dominant gms
msms (Fertile) MsMs/Msms (sterile)
No R-lines
(3) Seed Production of Recessive gms system
msms x MsMs Msms
A R R(F1 hybrid)
msms x Msms 1/2Msms+1/2msms
A B plant R × A
Self-reproduction
Seed production of Recessive GMS Lines
A line zone
50% msms
50%Msms
（ Double use line)
核不育两用系
R line zone
MSMS
×
A line zone
50% msms
50%Msms
（ Double use line)
核不育两用系
ISOLATION I ISOLATION II
MS line F1 hybrid
（ 4）双基因显性核不育 （含一个显性不育抑
制基因）的利用,
? 基因型 (RfRf 显性上位性基因）
不育系 MsMsrfrf (纯合两型系 )
Msmsrfrf (杂合两型系 )
恢复系 MsMsRfRf
msmsRfRf
半恢复系 _ _ Rfrf
临时保持系 msmsrfrf
? 表现型 Ms_ Rf_ 可育
MsmsRf 可育
Ms_ rfrf 不育
msmsrfrf 可育（为临保系）
? 双基因显性核不育系的临时保持
MsMsrfrf x msmsrfrf
（ 纯合两型系 ） （临保系）
Msmsrfrf
（杂合两型系,100%雄性不育）
（ 2） 纯合两型系的繁殖
MsMsrfrf x MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
1/2MsMsrfrf + 1/2MsMs Rfrf (授粉后淘汰 )
(不育 ) (可育 )
（四）核不育系的利用
1、用于杂交制种
（ 1）隐性核不育 ——―二系法,
（ 2）显性核不育 ——―三系法,
（ 3）采用染色体工程
·大麦 平衡三级三体
·玉米 缺失易位双杂合体
,小麦 X,Y,Z体系
（ 4）光敏核不育 制种
2、用于育种手段
·群体改良 —小麦太谷核不育利用
·远缘杂交等 (不需去雄 )
1,Self-incompatibility p.137
§ 6 Breeding and Utilization of Self-incompatible Lines
for Heterosis 自交不亲和系的利用
Self Incompatible Lines,
Perfect flowers
Normal gynaecium (Viable stigma)
Normal androecium (Viable pollens)
Self-pollination incompatible
Use for Heterosis,Hybrid crosses
Multiplication Problems,Selfing for pure lines
Multiplication Methods,
（ 1） Early pollination
(2) Spraying salt solution,3-8%
(3) Steel Brush treatment
(4) Chemical treatment
2,Multiplication of self-incompatible lines
3,Seed Production in the Self-incompatible
System 自交不亲和杂种的种子生产
SI
1
S1S1
SI
2
S2S2
SI
3
S3S3
SI
4
S4S4
SINGLE CROSS A SINGLE CROSS B
DOUBLE CROSS
SI
5
S5S5
3-WAY CROSS
Till Next Chapter
