1. Plant Genetics

2. Introduction
A plant species has common features that make it unique or different from other plant species.
These features may include growth habit, leaf shape, and or flower color

3. Every seed that a plant produces contains genetic material, or genes from the parent plant.
The ability of the plant to pass its unique characteristics to its offspring through this genetic material is referred to as inheritance or heredity

4. Phenotype vs. genotype
The phenotype of a plant refers to its observation traits or characteristics
Genotype is the plants genetic
makeup that gives the plant its phenotype

5. Two copies of every gene exist in the genotype.
These two copies of genetic material are called the alleles
An allele may be the dominant version of a trait or it may be the recessive version of the trait.
A dominant gene overrides the expression of a recessive gene for the same protein

6. Allele of a gene (trait) are coded for the same protein and are located in the same position on their respective chromosome
However the DNA code of a recessive allele is slightly different from that of the dominant allele for the same protein
This slight difference is visible through observable variations of the phenotype

7. When an individual plant has both dominant allele and recessive allele (heterozygous) only the dominant phenotype is visible.
The recessive phenotype appears only if an individual plant has two recessive alleles of the same gene ( homozygous)

8. Gregor Mendel He was an Australian Monk who was born in 1822
He is know as The Father Of Genetics
He discovered three laws of genetics that would forever change biology. He conducted a series of experiments in a monastery garden. Mendel spent 14 years growing and experimenting with pea plants.

9. Mendel gave three basic laws of inheritance
The Law of Dominance and Recessiveness
The Principle of Segregation
The Principle of independent Assortment
Mendel’s great contribution was to demonstrate that inherited characteristics are carried by genes.

10. Mendel chose for his experiments the garden pea
It was a good choice because
They were readily available
They were easy to grow
They grow rapidly
The sexual structures of the flower are completely enclosed within the petals so that there would be no accidental cross- pollination between plants.

11. Mendel's use of Pea plants for genetic experiments
Pea flowers are normally self pollinating. Since the male and female reproductive structures are relatively enclosed inside the flower. The sperm of the flower will fertilize the egg of the same flower
The resulting embryos will have the same characteristics as the parent plant. Even though sexual reproduction has occurred in just one parent

12. Mendel knew that these pea plants were “true-breeding”.
This means that is they are allowed to self pollinate they would produce offspring identical to themselves
For example: If allowed to self pollinate, tall plants would always produce tall plants. Plants with yellow seeds would always produce offspring with yellow seeds.

13. Mendel's Work
Mendel wanted to produce seeds by joining the egg and sperm from two different plants.
To do this he had to first prevent the possibility of self pollination.
Mendel cut away the stamens the male reproductive parts of the flower and then dusted the remaining female structure with pollen from a different plant
This is known as cross-pollination and produces offspring from two different parents.

15. Terms to know P generation- Parent generation
A couple of terms you need to be familiar with before we go any further.
P generation- Parent generation
F1 generation- First generation of offspring
F2 generation- Second generation of offspring
Hybrids- Offspring of parents with different traits.

16. Mendel Experiments
Mendel crossed true breeding tall plants with true breeding dwarf plants.
Tall x dwarf all Tall offspring
The F1 hybrids were all tall
All of the offspring had the appearance of only one parent
The trait of the other parent seemed to have disappeared.

17. Law of Dominance
In his observations, Mendel saw that the pea plants showed two contrasting characters for each of seven traits that became the basic of his studies.
Seed Shape ( round vs. wrinkled)
Seed color (yellow vs. green)
Seed coat color ( gray vs. white)
Pod color (green vs. white)
Pod shape ( smooth vs. wrinkled)
Plant height ( tall vs. short)
Flower position ( axial vs. terminal)

19. The plants Mendel produced through cross- pollination were hybrids
The genotype of these plants were heterozygous, which means they had different alleles (dominant and recessive) for the same gene.
Homozygous genes were those in which the two alleles were the same

20. From his research, Mendel concluded that equal blending of characteristics did not occur in the cross-pollination of pea plants.
Mendel also found that some were dominant over other characteristics being expresses visually in the phenotype

21. Law of segregation
Continuing his research, Mendel wanted to find out what happened to the recessive characters in the F1 generation, so hr allowed the hybrid F1 plants to self pollinate.
In the resulting F2 generation, Mendel observed that each recessive trait he was studying reappeared in 25% of the offspring.
Mendel referred to this 3:1 ration as the law of segregation

22. There are alternative forms of genes, the units determining heritable characteristics. This is now known as an allele
An organism inherits one allele from each parent. The F1 generation inherited one green and one yellow pod allele from the parental generation.
A sperm or egg carries only one allele for each characteristic which pair upon fertilization.
When the alleles are different, one is fully expressed and the other is masked, now known as dominant and recessive genes.

25. The resulting combination shows genotypes of ¼ homozygous dominant (TT), ½ heterozygous (Tt), and ¼ homozygous recessive (tt)

26. The phenotype of the offspring are ¾ dominant and ¼ recessive
The phenotypic ration of 3:1 agrees with what Mendel observed in the F2 generation that showed 25% of the plants with the recessive characteristic

27. Law of Independent Assortment
After Mendel realized that gene segregate when gametes are produced, he continued his research to find out if a gene that controls one trait affects the genes that control other traits.
By cross-pollination plants with different trait , Mendel observed that the recessive phenotypes were again not visible in the F1 generation.

28. Now knowing that the recessive traits were hidden in the F1 generation, Mendel allowed the heterozygous F1 hybrids to self pollinate.
If the f1 parents had independent genes, four combinations of gametes would be produced; only two possibilities would occur if the genes were linked.

29. In his result, Mendel found that the recombination of traits showed that the plant genes for each trait did, indeed, sort independent of each other
This recombination of traits increases the diversity of the population of plant species.

30. Why is this important??
In today's world plant producers look for genes to make crops resistant to diseases and insects.
Using modern advancements and techniques in biotechnology, scientists are able to copy beneficial or desirable plant allies in lab settings and use them to replace or complement existing genes to improve a plant.