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Applied Genetics in Agriculture and Agriscience

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Cross Pollination-Step 2 Pollen can be gathered from ... Tissue Culture Common method of asexual production utilizing extremely small amounts of plant material ... – PowerPoint PPT presentation

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Title: Applied Genetics in Agriculture and Agriscience


1
Applied Genetics in Agriculture and Agriscience
  • Competency 16.00

2
Sexual Reproduction Terms
  • Fertilization-the union of haploid cells in both
    plants and animals
  • Occurs in the ovary of plants and the uterus of
    animals

3
Sexual Reproduction Terms
  • Embryo-a fertilized egg/ovule that will grow to
    produce new offspring

4
Sexual Reproduction Terms
  • Ovary-organ responsible for the production of
    eggs/ova in plants and animals

5
Sexual Reproduction in Plants
6
Pollination
  • The transfer of male pollen to the female
    reproductive organs
  • Pollination must occur before fertilization
  • Removal of the stamen is the first step in
    mechanical cross pollination

7
Germination
  • The initial vegetative growth of a seed

8
The Stamen
  • Male reproductive parts
  • Anther-top of the male flower, contains pollen
  • Filament-long slender stock on which the anther
    sits

9
The Stamen
10
The Pistil
  • Female Reproductive Parts
  • Stigma-the swollen end of the pistil, sticky to
    receive the pollen
  • Style-stalk connecting the stigma to the
    ovary-pollen on the stigma forms long tubes
    through the style
  • Ovary-produces and stores the ova (seeds), and
    protects seeds during development
  • 1 ovum1 seed and 1 ovary1 fruit

11
The Pistil
12
Types of Flowers
  • Complete-have all the parts of a flower (Stamen,
    Pistil, Sepals, Petals)
  • Incomplete-missing any part of the flower

13
Types of Flowers
  • Perfect-have all the reproductive parts of a
    flower (Stamen and Pistil)
  • Imperfect-missing any reproductive part of the
    flower

14
Cross Pollination
  • The method used to select particular parents for
    the production of seeds in plants.

15
Cross Pollination-Step 1
  • Plants possessing desirable characteristics are
    selected and carefully monitored.

16
Cross Pollination-Step 2
  • Pollen can be gathered from male plants (or
    flowers) or in some cases, years in advance and
    refrigerated for storage.

17
Cross Pollination-Step 3
  • Flowers on the female plant must be covered prior
    to opening, and if capable of self-pollination,
    must have the stamens removed.

18
Cross Pollination-Step 4
  • Once the female flowers open, pollen from the
    male should be placed on the stigma, and the
    flower covered again.
  • Record keeping is critical in crossing plants.

19
Asexual Reproduction in Plants
20
Stem Cuttings
  • Section of the stem or branch is cut, treated
    with a rooting hormone, and placed in soil or
    water to encourage the development of roots.

21
Stem Cuttings
  • Should always be taken just above a node for best
    rooting.
  • Most common method of asexual propagation, used
    for both woody and herbaceous plants.
  • Can also do leaf and root cuttings.

22
Air Layering
  • Section of the stem or branch has the bark
    removed or slightly damaged and a rooting hormone
    applied.
  • The area is then covered with soil, wrapped in
    cellophane until well developed roots can be seen
    through the plastic.

23
Air Layering
  • The branch or stem is cut below the roots only
    after roots have fully developed.

24
Tissue Culture
  • Common method of asexual production utilizing
    extremely small amounts of plant material
  • Often uses meristem tips-the tip of a branch
    where most active growth is occurring

25
Tissue Culture
  • Tissue is removed from the plant, sterilized and
    cultured on agar in aseptic conditions.
  • Meristematic tissue develops shoots, is
    transferred to another media to develop
    adventitious roots, is hardened off, and finally
    transferred to soil.

26
Division
  • Method of plant propagation conducted by
    physically separating a plant into several
    smaller plantlets.
  • Often used for grasses and lilies
  • A variation is the production of non-tunicate
    bulbs from scales (each scale must contain a part
    of the bottom of the bulb, the basal plate.

27
Grafting
  • The process of removing plant material from one
    plant for incorporation into another plant
  • Often used with fruit trees to create dwarf
    varieties

28
Grafting-2 Parts
  • Scion-the top portion of a graph that will form
    the main part of the plant.
  • Rootstock-the bottom portion of the graft that
    usually controls growth habit (size of the plant)
    but produces no vegetation

29
Grafting-2 Parts
30
Budding
  • Related to grafting
  • Instead of using a scion, exchange of plant
    material is accomplished with a single bud

31
Grafting and Budding
  • SCION AND ROOTSTOCK REMAIN GENETICALLY DISTINCT
    EVEN AFTER COMBINATION

32
Sexual Reproduction in Animals
33
Fertilization
  • Occurs internally in most animals-all mammals
  • Some fish and insects are exceptions

34
Haploid Cells
  • Male cells are spermatazoa (sperm)
  • Released in semen to aid in the process of
    fertilization

35
Haploid Cells
  • Female cells are eggs
  • Produced in the ovary
  • Fertilized and developed within the uterus
  • Females release eggs on a cycle (menstrual cycle)
    that varies in time length according to species

36
Selective Breeding Techniques in Animals
37
Progeny Testing
  • Determines the value of male livestock by
    analyzing the transmission of traits to offspring
    and its breeding potential

38
Artificial Insemination
  • Proven to have the greatest impact on animal
    breeding since the first domestication of
    livestock

39
AI Process
  • Semen is collected from male individuals-methods
    vary widely by the type of animal
  • Artificial vaginas are used for larger mammals

40
AI Process
  • Semen is checked for viability and flash frozen
    in specialized straws
  • Straws should be placed in storage tanks filled
    with liquid nitrogen until use
  • Semen stored under proper conditions has proven
    viable decades later (-320 degrees F)

41
AI Process
  • Female is treated with prostaglandin (hormone) to
    induce estrus or heat

42
AI Process
  • Semen straws are immediately thawed in water (99
    degrees F) and soon after inserted into the
    mother using a specialized release gun.

43
AI Process
44
Sperm Sexing
  • Utilizes a cytometer cell sorter to separate male
    sperm from female sperm
  • Sperm with X chromosomes (female) weigh more
    (contain more DNA) than those with a Y and can be
    dyed and separated because they absorb more dye

45
In-vitro Fertilization
  • A large number of eggs are collected from the
    ovaries of an outstanding female and fertilized
    in Petri dishes under laboratory conditions
  • Embryos can be inserted into a surrogate or
    frozen
  • Offers the most control and requires the least
    amount of semen.

46
Surrogacy
  • Hormones are used to cause the female to
    superovulate (produce a large number of eggs)

47
Surrogacy
  • Original mother undergoes artificial insemination
  • Fertilized eggs are removed by a process called
    FLUSHING to be placed in other female animals for
    development.

48
Cloning
49
Cloning
  • Allows rapid production of large numbers of
    genetically identical organisms
  • Agriculturists can quickly disseminate
    outstanding traits

50
Cloning
  • Clones are genetically identical (the exact same
    DNA)
  • Any genetic differences results from
    environmental factors-disease, nutrition,
    physical injuries, etc.

51
Plant Cloning
  • Most often utilized for the culture of plants
  • Cheaper, easier process
  • Less political opposition
  • The ability to differentiate is more in plants
    than animals.

52
Plant Cloning
  • Tissue culture-the production of plants from
    small amounts of vegetative materials in an
    in-vitro environment
  • An increasingly popular and effective method of
    plant production

53
Animal Cloning
  • Animals are cloned almost exclusively by the
    division of embryos
  • In recent years, diploid cells have been cloned,
    but the process is extremely expensive and
    results in high losses

54
Animal Cloning
  • Dolly the sheep was produced from mammary gland
    cells in a sheep

55
Transgenic Organisms
56
Transgenic Organisms
  • Can potentially be created using genes from any
    living organism
  • The trick is finding a method for insertion and
    successful expression

57
Transgenic Organisms
  • Genetically modified organisms transmit inserted
    genes at the same rate as naturally occurring
    genes
  • Once a gene is inserted, it can be passed on
    through sexual reproduction

58
Creating a Transgenic Organism
59
Step 1
  • Develop a purpose/goal
  • The transmission of genes from one organism to
    another is both expensive and potentially
    dangerous, expectations for work should be laid
    out carefully.

60
Step 2
  • DNA must be extracted from the target organism
    and the specific gene to be introduced isolated
    utilizing restriction enzymes

61
Step 3
  • Vectors are used for the transmission of target
    genes
  • Viruses make good vectors, as they often insert
    DNA into organisms they affect
  • Plasmids are the viruses most used
  • Plasmids can store large strands of DNA or even
    one or more chromosomes

62
Step 3-continued
  • Some vectors can transmit genes simply through
    contact with target cells in a liquid solution or
    by microinjection.

63
Step 4
  • Isolated DNA is inserted into the new organism by
  • Micromanipulation
  • Biolistics

64
Micromanipulation
  • The isolated DNA segment is injected into a
    target cell utilizing a microscopic syringe under
    high magnification
  • Most common form of gene insertion

65
Biolistics
  • Used a gene gun to fire gold plated .22 caliber
    shells that have been covered with the target
    gene into a mass of plant cells
  • Most often used for plants
  • Cell mortality is high
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