Selectively Plant Bleeding

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Selectively Plant Bleeding
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Introduction
Look around us, we often see packed crops and
fruits spamming the supermarket or wet market,
fiber-containing foods have doubtlessly been
taken in our diets since we were born.
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However
Have you ever thought that what we are eating
and enjoying are indeed originated from the
agriculture technology?
Have you ever thought that why they are so
sweetie and giant and quantity-guaranteeing?
Here comes our answer
PLANT BREEDING
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No doubt that all of you know plant-breeding is
involved in producing such special yields now.
Indeed, defects of plant breeding are very
limited, contrary to that, it is great beneficial
to humanity and human mankind.
Before looking into the reasons behind, lets us
introduce its background first. Plant breeding is
originated from western countries in early
centuries, Do bear in mind that they are not GM
food. Thank you
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About the Content
We may continue to explore the great fun of plant
breeding now.
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Benefits
Nowadays, with the technology of plant
breeding, such benefits are guaranteed as follow
Improving the quality of the products
Ensuring the quality of the products
Possessing the desired characteristics
Buffering the crop against pathogens
- stability of production under varied
environmental conditions
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Methods
Self-fertilization

• Pollen from a plant can fertilize the
  reproductive cell
• or ovule of the same plant

Self-fertilization
F1
F2
- Homozygosity?
Hybridization
F3
Cross-pollination
F4
- Pollen from one plant can only fertilize a
different plant
- Heterozygosity?
Back-crossing
- Pollen from offspring plant can only fertilize
its parents plant
- A selection method for the upgrading of
genotypes
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Asexual propagation
- Gives a new plant which is genetically
identical to its parent plant
- To ensure the quality of the products
Doubled haploid method(polyploidy)
- Double the chromosome numbers of the haploid
plants

• During the cell division, treat the cell with
  chemicals such as
• colchicines to inhibit the spindle formation

- The appearance of new species enhances the
chance of survival with the changing
environment
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Examples
Self-pollination
The stamens actually grow into contact with the
pistil to transfer the pollen.
Peach
Peaches are not truly self- pollinated, as it is
generally an insect pollinator.
However, peaches are considered self-fertile
because a commercial crop can be produced without
cross-pollination.
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Cross-pollination
Like most perennial fruits, apples are
ordinarily propagated asexually by grafting.
Apple
Some breeders have crossed ordinary apples with
crabapples or unusually hardy apples in order to
produce hardier cultivars.
The hybrid of an orchard apple with a red-fruited
crabapple cultivar.
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To Know More
Crabapple is a kind of apples that have the same
Genus Malus with apple.
They are used as pollenizers in apple orchards.
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Citrus
Citrus is a common term and genus of flowering
plants Lemon and orange
Citrus trees hybridize very readily.
The desired fruiting cultivars can be bred. E.g.
Seedless orange.(The seeds are very small)
All commercial citrus cultivation uses trees
produced by grafting the desired fruiting
cultivars selected by cross-fertilization for
disease resistance and hardiness.
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Polyploidy in plant
DefinitionMore than two sets of chromosomes per
nucleus
The number of chromosome sets in the
nucleus triploid (three sets 3n), tetraploid
(four sets 4n), pentaploid (five sets 5n),
hexaploid (six sets 6n) and so on.
Parents (2n)AA x (2n)BB
AB genome
Gametes (n)A (n)B
Hybridization (2n)ABsterile
Treatment with chemicals (colchicines)poisonous
Polyploidy Chromosome doubling
(4n)AABBfertile
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Autopolyploidy
Definitionduplication of sets of chromosomes
involving only one species
-not common in nature, but frequent in cultivated
plants -create a genetic potential hybrid for
breeding(making 3n/4n/6n.)
A A -genetic manipulation? A A A A
Species A
Species A
Allopolyploidy
Definitionthree or more sets of
chromosomes, derived from two or more different
species

• can arise from a naturally occurring spontaneous
  genome doubling
• -new species can be obtained

A A B B B B -genetic manipulation? AABBBB
Species A
Species B
Species C
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Examples of Polyploidy
Nowadays, polyploidy is a widely used technique
in plant breeding.
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Sweet potatoes
Selection of genome for polyploidy
wheat
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The production of Seedless watermelon
Example of Autopolyploidy
Triploid 3n
Female Parent (2n)
Watermelon
Genetic manipulation(colchicines)
Female Parent (4n) x Male Parent(2n)
striped
Green without striped
Triploid seed(3n)
Pollenized by a diploid plant(2n)
Seedless watermelons have far fewer seeds than
the seeded varieties, they generally contain at
least a few soft, pale seeds.
Seedless Watermelon (3n)
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Example of Allopolyploidy
Triticale(???)
(Triticosecale Wittmack)
Introduction
- an artificial hybrid of rye(Secale cereale)??
and wheat (Triticum turgidum)?? - The first bred
is in laboratories during the late 19th century -
2 type of Triticale Hexaploid(6n)
octaploid(8n) Triticale
wheat
rye
triticale
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The steps involved in Hexaploid(6n)Triticale
Parents Female parentwheat (4n) x Male
parentrye (2n)
Gametes AA (2n)
B (n)
Hybridization
AAB(3n)sterile
Polyploidy Chromosome
doubling
be treated with the alkaloid colchicine
Triticale AAAABB(6n)fertile
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The steps involved in Octaploid(8n)Triticale
Parents Female parentwheat (6n) x Male
parentrye (2n)
Gametes AAA (3n)
B (n)
Hybridization
AAAB(4n)sterile
Polyploidy Chromosome
doubling
be treated with the alkaloid colchicine
Triticale AAAAAABB(8n)fertile
Hexaploid(6n)Triticale is more tough than
Octaploid(8n)Triticale. So, hexaploid triticale
has a higher potential on production. Hexaploid(6n
)Triticale was selected for the continuous
research of breeding.
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Significance of Triticale

• Healthy food
• A source of making bread(the quality is a bit
  worse than wheat)
• Forage of livestock

Mixed advantage on planting
-the high yield and good properties for
bakingFrom wheat -with the resistance to harsh
climatelow requirements for soil qualityFrom rye
The grain of wheat , rye
triticale. Triticale grains are significantly
larger than wheat.
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Autoallopolyploid
Definition contains duplicated sets from one
species plus at least one set from a different
species
Example Coast Redwood(Sequoia sempervirens)
Introduction
It is an evergreen, long-lived, monoecious tree
living for up to 2,000years, and is commonly
considered the tallest tree in the world,
reaching up to 112 m in height and 7 m diameter
at the base.
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Genetic makeup
-hexaploid (6n)
-autoallopolyploid (AAAABB)
Its complement-AA belongs to Stebbins(Metasequoia
Glyptostroboides) "1A"
Its complement-B belongs to karyotypic
type(Sequoiadendron giganteum) "1B"
They mixed and duplicate to form Sequoia
sempervirens
Data sourceDepartment of Biology, F. U.,
Shanghai (1987). The origin of Sequoia-sempervire
ns Taxodiaceae based on karyotype. Acta Botanica
Yunnanica 9(2) 187-192.