genetics and genetic prediction in plant...

Genetics and

Genetic Prediction

in Plant Breeding

2010

Qualitative Genetics

Controlled by alleles at a single locus

Quantitative genetics

Controlled by polygenic systems

Population Genetics

Frequency of alleles in populations

Cytogenetics

Properties of chromosomes.

Molecular Genetics

Involves studies at the molecular level

Qualitative Genetics

Segregation, linkage,

epistasis, tetraploid, 2

Quantitative Genetics

Continuous variation, genetic

models, model testing

QTL’s

Heritability

Broad-sense & narrow-sense

Diallel

Griffing analysis, GCA, SCA

Hayman & Jink’s

Cross prediction

Augustinian Monk, St.

Thomas in Brünn.

Started genetics work with

pea in 1856.

Published genetics paper

1866 (ignored).

Vries, Correns, Tschermak

(independently) rediscover

Mendel's work.

Gregor Johann Mendel

Parents F1

Progeny

F2

Progeny

F2

Dom:Rec

round x wrinkled round 5,474 rd

1,850 wr 2.96 : 1

yellow x green yellow 6,022 ye

2,001 gr 3.01 : 1

long x short stem long 787 lo

277 sh 2.84 : 1

axil x terminal axil 651 ax

207 ter 3.15 : 1

Chose Pisum Sativum as a research species.

diploid species.

homozygous parental lines. Did research beyond the F2 generation.

Concentrated on qualitatively inherited characters.

Kept meticulous records of plant counts and could

trace lineage of all progeny.

Genotype ?

Phenotype. Environment.

Large effect on quantitative traits, small effect on qualitative traits.

Dominance (allelic interactions). Expression on one allele is masked by another

allele at the same locus.

Epistasis (non-allelic interactions).

Expression of one allele is masked by another allele at a different locus.

Parents tall x dwarf 6-row x 2-row


F1 tall 6-row


F1 tall 6-row

F2 3 tall:1 short 3 6-row : 1 2-row


F1 tall 6-row

F2

3 tall:1 short

TT:Tt:tt

1:2:1

3 6-row : 1 2-row

SS:Ss:ss

1:2:1

Parents AA x aa

F1 Aa

F2

Frequn

AA

¼

Aa

½

aa

¼

F3

Frequn

AA

¼

AA

1/8

Aa

¼

aa

1/8

aa

¼

3/8 ¼ 3/8

F1

TtSs

Self

TS Ts tS ts

Gametes from

female parent

Gametes from male parent

TS Ts tS ts

TS

Ts

tS

ts

Gametes from

female parent


TS Ts tS ts

TS TSTS

Ts

tS

ts

Gametes from

female parent


TS Ts tS ts

TS TSTS TSTs TStS TSts

Ts TsTS TsTs TstS Tsts

tS tSTS tSTs tStS tSts

ts tsTS tsTs tstS tsts

Gametes from

female parent


TS Ts tS ts

TS TTSS TTSs TtSS TtSs

Ts TTSs TTss TtSs Ttss

tS TtSS TtSs ttSS ttSs

ts TtSs Ttss ttSs ttss

Gametes from

female parent


TS Ts tS ts





1 TTSS:2 TTSs:1 TTss:2 TtSS:4 TsSs:2 Ttss:1 ttSS:2 ttSs:1 ttss

Gametes from

female parent


TS Ts tS ts


Ts TTSs TtSs

tS TtSS TtSs

ts TtSs

Gametes from

female parent


TS Ts tS ts

TS

Ts TTss Ttss

tS

ts Ttss

Gametes from

female parent


TS Ts tS ts

TS

Ts

tS ttSS ttSs

ts ttSs

Gametes from

female parent


TS Ts tS ts

TS

Ts

tS

ts ttss

Gametes from

female parent


TS Ts tS ts





9 T_S_ : 3 T_ss : 3 ttS_ : 1 ttss

F2

Gametes TT – ¼ Tt – ½ tt – ¼

SS – ¼ 1/16 TTSS 2/16 TtSS 1/16 ttSS

Ss – ½ 2/16 TTSs 4/16 TtSs 2/16 ttSs

ss – ¼ 1/16 TTss 2/16 Ttss 1/16 ttss

9 T_S_ : 3 T_ss : 3 ttS_ : 1 ttss

1TTSS: 2TTSs:1TTss:2TtSS: 4TsSs: 2Ttss:1ttSS: 2ttSs:1 ttss

F3

Gametes TT – 3/8 Tt – 2/8 tt – 3/8

SS – 3/8 9/64 TTSS 6/64 TtSS 9/64 ttSS

Ss – 2/8 6/64 TTSs 4/64 TtSs 6/64 ttSs

ss – 3/8 9/64 TTss 6/64 Ttss 9/64 ttss

25 T_S_ : 15 T_ss : 15 ttS_ : 9 ttss

9 TTSS:6 TTSs:9 TTss:6 TtSS:4 TsSs:6 Ttss:9 ttSS:6 ttSs:9 ttss

F2 TTSS TTSs TTss TtSS TtSs Ttss ttSS ttSs Ttss

1/16 2/16 1/16 2/16 4/16 2/16 1/16 2/16 1/16

F2 TTSS TTSs TTss TtSS TtSs Ttss ttSS ttSs Ttss

4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

F3 F2

TTSS TTSs TTss TtSS TtSs Ttss ttSS ttSs ttss

4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS 4

TTSs -

TTss -

TtSS -

TtSs -

Ttss -

ttSS -

ttSs -

ttss -

F3 F2


4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS 4 2

TTSs - 4

TTss - 2

TtSS - -

TtSs - -

Ttss - -

ttSS - -

ttSs - -

ttss - -

F3 F2


4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS 4 2 -

TTSs - 4 -

TTss - 2 4

TtSS - - -

TtSs - - -

Ttss - - -

ttSS - - -

ttSs - - -

ttss - - -

F3 F2


4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS 4 2 - 2 1 - - - -

TTSs - 4 - - 2 - - - -

TTss - 2 4 - 1 2 - - -

TtSS - - - 4 2 - - - -

TtSs - - - - 4 - - - -

Ttss - - - - 2 4 - - -

ttSS - - - 2 1 - 4 2 -

ttSs - - - - 2 - - 4 -

ttss - - - - 1 2 - 2 4

F3 F2

TTSS TTSs TTss TtSS TtSs Ttss ttSS ttSs ttss Total

4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS 4 2 - 2 1 - - - - 9

TTSs - 4 - - 2 - - - - 6

TTss - 2 4 - 1 2 - - - 9

TtSS - - - 4 2 - - - - 6

TtSs - - - - 4 - - - - 4

Ttss - - - - 2 4 - - - 6

ttSS - - - 2 1 - 4 2 - 9

ttSs - - - - 2 - - 4 - 6

ttss - - - - 1 2 - 2 4 9

F3 F2

TTSS TTSs TtSS TtSs Total

4/64 8/64 8/64 16/64

TTSS 4 2 2 1 9

TTSs - 4 - 2 6

TTss - 2 - 1 3

TtSS - - 4 2 6

TtSs - - - 4 4

Ttss - - - 2 2

ttSS - - 2 1 3

ttSs - - - 2 2

ttss - - - 1 1

F3 F2

TTSS TTSs TTss TtSS TtSs Ttss ttSS ttSs ttss Total

4/64 8/64 4/64 8/64 16/64 8/64 4/64 8/64 4/64

TTSS - - 0

TTSs - - 0

TTss - - 0

TtSS - - 0

TtSs - - 0

Ttss - - 0

ttSS 4 2 6

ttSs - 4 4

ttss - 2 2

Selection

stage

Dominant

Character

Recessive

Character

1 trait 2 trait 1 trait 2 trait

F2 75% 56% 25% 6%

F3 63% 39% 37% 14%

F4 56% 32% 44% 19%

F 50% 25% 50% 25%

Selection

Selection

stage

Dominant

Character

Recessive

Character

1 trait 2 trait 1 trait 2 trait

F2 +33 % +55 % -33 % -20 %

F3 +21 % +35 % -21 % -13 %

F4 +11 % +22 % -11 % -7 %

F 0 % 0 % 0 % 0 %

Mis-selection

Linkage (allelic

interactions) & Epistasis

(non-allelic interactions)

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