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Glossary
Sections:
Introduction
Principles of inheritance
Genotypic variation
Other forms of heritable variation
Quantitative variation and heritability
Novel sources of genetic variation
The practice of plant breeding
Breeding methods
Breeding methods
Self pollinators: Mass selection
Self pollinators: Pure line selection
Self pollinators: Pedigree selection
The pedigree breeding funnel: wheat example
Self pollinators: Single seed descent and doubled haploid lines
Single seed descent
Single seed descent, contd
Doubled haploids
Self pollinators: Back-cross breeding
Self pollinators: male sterility and F1 hybrids
Manual emasculation
Chemical sterilization
Genetic male sterility
Cross pollinators: F1 hybrids
Cross pollinators: F1 hybrids, contd
Polyploids
Polyploids contd
Ploidy level affects fertility
Autopolyploid breeding
Alloployploid breeding
Vegetatively propagated crops
Tree crops
Participatory plant breeding
Plant Breeders' rights
New technologies for plant breeding
Untitled Document

Polyploids contd

The familiar Mendelian ratios apply to genetic segregation in allopolyploids, but not to autopolyploids

Tetrasomic inheritance from selfing of Aaaa:

 

The numbers indicate the dosage of A in the zygote

 

AA

Aa

Aa

Aa

Aa

aa

AA

4

3

3

3

3

2

Aa

3

2

2

2

2

1

Aa

3

2

2

2

2

1

Aa

3

2

2

2

2

1

Aa

3

2

2

2

2

1

aa

2

1

1

1

1

0

1 AAAA: 8 AAAa: 18 Aaaa: 8 Aaaa: 1 aaaa 

or

35 A---: 1 aaaa

Contrast with the familiar diploid Mendelian ratio:

1 AA: 2 Aa: 1 aa

or  

3 A- : 1 aa