1. Overview What is Plant Breeding? Basic Genetics Mendelian Genetics
Principles of Breeding
Plant Breeding Methods
Molecular breeding introduction

2. Plant Breeding Molecular breeding introduction What is it?
Is the science and art of improving crop plants through the study and application of genetics, agronomy, statistics, plant pathology, entomology, and other related sciences.
Goals
Nutritional enhancement, yield improvement, environmental stress tolerance, improved plant structure, or pest and disease resistance
Molecular breeding introduction

3. OBJECTIVE OF THE SUBJECT
understand the developments in plant breeding and the state of the art breeding practices (ornamentals vs. crops)
have some knowledge on the basics of genetics (Mendel, QTL etc.) and understand the idea and the potential of genetic engineering
have some understanding on the concepts of molecular breeding
have some (practical) knowledge to apply molecular markers for the identification of traits in the genome
be able to determine whether information from the internet
regarding modern breeding methods are relevant and informative
Molecular breeding introduction

4. Selected milestones in plant breeding
1714 Mather observed natural crossing in maize
1866 Mendel: Experiments in plant hybridization
1900 Mendel’s laws of heredity rediscovered
1944 Avery, MacLeod, McCarty discovered DNA is hereditary material
1953 Watson, Crick, Wilkins proposed a model for DNA structure
1970 Borlaug received Nobel Prize for the Green Revolution
Berg, Cohen, and Boyer introduced the recombinant DNA technology
1994 ‘FlavrSavr’ tomato developed as first GMO
1995 Bt-corn developed
Molecular breeding introduction

5. Importance of plant breeding
Difference in :
- yield
- content
- germination
- maturation
- resistance
Importance of plant breeding
1.Increased quality and yield of the crop
2. Increased tolerance of environmental pressures (salinity, extreme temperature, drought)
3. Resistance to viruses, fungi and bacteria
4. Increased tolerance to insect pests
5. Increased tolerance of herbicides
Molecular breeding introduction

6. Molecular breeding introduction

7. Basic Plant Genetics DNA Primary carries of heritable information
Composed of thousands of genes

9. Molecular breeding introduction

10. Molecular breeding introduction

11. Basic Plant Genetics There are two alleles for any gene
Dominant and Recessive
Two dominant alleles are denoted as “AA” and
called homozygous dominant
Two recessive alleles are denoted as “aa” and
called homozygous recessive
If one dominant and one recessive allele is present then it is denoted as “Aa” and called heterozygous.
Molecular breeding introduction

12. Basic Plant Genetics
Alleles which are heterozygous or homozygous affect the phenotypes and genotypes of plants
Phenotype
Visual appearance of the plant
Genotype
Genetic makeup of the plant
Molecular breeding introduction

13. Mendelian Genetics Gregor Mendel Famous geneticist from 1800’s
His research consisted of selectively breeding garden peas
He developed two important laws of genetics
Law of Segregation
Law of Independent Assortment
Molecular breeding introduction

14. Mendelian Genetics
Molecular breeding introduction

15. Principles of Breeding
Three Main Principles
Inbreeding
Hybridization
Heterosis
Steps of Plant Breeding
plant breeding;
Creation of variation
Selection
Evaluation
Release
Multiplication
Distribution of the new variety
Molecular breeding introduction

16. Inbreeding
Main Goals
Increase the homozygosity at all or specific loci in the plant genome
Produce a plant which breeds true
Produce uniform plants
Molecular breeding introduction

17. Hybridization
Hybridization occurs when inbred parents are mated (cross pollinated)
Creates a heterozygous individual
Benefits
Increased heterosis (vigor) in F1 generation
Molecular breeding introduction

18. Heterosis
Heterosis occurs when two homozygous individuals are cross pollinated.
This causes all loci to become heterozygous
The increased heterozygosity causes increased plant vigor
Benefits of Increased Vigor
Increased yield
Better standability
Better germination
Overall better plant performance
Molecular breeding introduction

19. Breeding Methods Main Methods of Breeding Selfing (Inbreeding)
Sib Mating
Crossing
Test Crossing
Backcrossing
Molecular breeding introduction

20. Selfing
Selfing is the process of pollinating a plant with its own pollen
Benefits
Increased homozygosity
Plants which breed true from generation to generation
Decreased Segregation
Disadvantages
Many generations of selfing lead to inbreeding depression
Molecular breeding introduction

21. Molecular breeding introduction

22. Crossing and Test Crossing
Crossing is useful when trying to create hybrid seed.
Ex. By crossing “Inbred A x Inbred a” you would obtain an F1 hybrid Aa
Crossing is used to produce the hybrid seed farmers use to plant in the spring
Test Crossing is useful to test general combining ability of an individual
Ex. Inbred A is x to a tester which has a diverse selection of genotypes
Molecular breeding introduction

23. Molecular breeding introduction

24. Backcrossing
Backcrossing is a method which is used to improve a trait which a plant is deficient in.
Method
A hybrid plant which has the trait of interest is crossed with one of its parents
The offspring are then crossed back to the parent, thus increasing the frequency of the trait.
Molecular breeding introduction

25. Scientific disciplines and technologies of plant breeding
Genetics
Botany
Plant physiology
Agronomy
Pathology and entomology
Statistics
Biochemistry
Molecular breeding introduction

26. Classic/ traditional tools
Emasculation
Hybidization
Wide crossing
Selection
Chromosome counting
Chromosome doubling
Male sterility
Triploidy
Linkage analysis
Statistical tools
Advanced tools
Mutagenesis
Tissue culture
Haploidy
In situ hybridization
DNA markers
Molecular breeding introduction

27. Advanced technology Molecular markers Marker-assisted selection
DNA sequencing
Plant genomic analysis
Bioinformatics
Microarray analysis
Primer design
Plant transformation

28. Conclusion Plant breeding is a complicated but beneficial process.
There are many processes involved which are used in the development of new varieties.
Remember if it wasn’t for plant breeding we wouldn’t have such high yielding crops

29. Mendal’s law of genetics
Next topic:
Mendal’s law of genetics
Mendal’s law of genetics