Download Genetics & Plant Breeding

Genetics & Plant Breeding
J.G. Mexal
A/H 100 G
Spring 2006
Topics
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History
Cell Division (mitosis)
Reproduction (meiosis)
Role of DNA
Role of RNA
Plant Breeding & Genetics
Gregor Mendel (1822-1864)
• Worked in monastery
garden
• Time period = 1856-1863
• Published: “Experiments
on Plant Hybrids” in
obscure journal
• Worked ‘discovered’ in
1900
Gregor Mendel
• Dominant vs
Recessive genes
S = smooth
s = wrinkled
Gregor Mendel
• Dominant vs Recessive genes (2)
F1
S = smooth
s = wrinkled
Y = yellow
y = green
Gregor Mendel
• Incomplete dominance
Important Milestones
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1866 Gregor Mendel
1947 Barbara McClintock (jumping genes)
1953 Watson & Crick (structure of DNA)
1970s Foreign gene expressed in tobacco
1986 Transgenic plants field tested
1990s Bt gene inserted into crops
1994 Flavr-Savr tomato released
Sex in the Garden
Types of Propagation
#10
#9
#8
#7
#6
#5
#4
#2
#1
Sex in the Garden
Types of Propagation
• Sexual
– Self-pollination
-- Wind pollination
– Cross-pollination -- Insect pollination
• Asexual
– Cuttings
– Grafting
-- Layering
-- Biotechnology
Sex in the Garden
Sexual Propagation
• Terms
– DNA : Deoxyribonucleic Acid a polymeric
molecule consisting of nucleotides (ribose, PO4, and
adenine, cytosine, guanine, & thymine). Found in
nucleus, chloroplasts, mitochondria. Makes RNA.
– RNA: Ribonucleic Acid a polymeric molecule
consisting of nucleotides (ribose, PO4, and adenine,
cytosine, guanine, & uracil). Found in nucleus,
chloroplasts, mitochondria, ribosomes. Makes
proteins.
Building Blocks
Sex in the Garden
Sexual Propagation
Terms
– Chromosome: genetic material of cell organized in
linear structures
– Gene: genetic material on a chromosone
determining a characteristic
– Genotype: the genetic makeup of an organism
– Phenotype: the physical manifestation of the
genotype modified by the environment
Sex in the Garden
Sexual Propagation
Terms
– Diploid: a cell containing 2 sets (2n)of
chromosomes (vegetative cell)
– Haploid: a cell containing 1 (1n)set of
chromosomes (pollen or ovule)
– Polyploid: a cell containing more than 2 sets of
chromosomes. Usually vegetatively reproduced.
• Banana
=
• Potato
=
• Strawberry =
3n
4n
8n
Sex in the Garden
Sexual Propagation
Terms
– Mitosis: cell division where nuclear complement (1n
or 2n) is maintained
– Meiosis: cell division where nuclear complement
(2n only) is reduced to 1n (gametes)
– Hybridization: controlled cross-fertilization
– Independent Assortment: each chromosome
operates independently during mitosis & meiosis
– Mutation: a heritable change in a gene
Sex in the Garden
Sexual Propagation
Terms
• Monoecious: Both sexes on same plant
(e.g. corn, pecan)
• Dioecious: Sexes on different plants
– Holly (female)
Juniper (male or female)
– Pistachio (female) Cottonwood (male)
– Asparagus (male)]
– Ash (male)
Cell Division-Mitosis
Cell Division-Meiosis
Sexual Propagation
Meiosis
Ovule
Pollen
#10
#9
#8
#7
#6
#5
#4
#2
#1
Flower
microspores
megaspores
Sexual Propagation
Fertilization
Generative cell
Tube nucleus
Sperm cells
Polar nuclei
Pollen grain
Egg
Pollen tube
Embryo sac
Endosperm
3n
Zygote 2n
Embryo
2-nucleate
4-nucleate
Genetic Engineering
• The Plan:
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Find a gene of interest
Develop cell culture of crop
Insert the gene (tools)
Hope it gets incorporated in
plant DNA
– Have gene product expressed
– Regenerate plants from cells
– Field test to see if it works!
• The Tools
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Agrobacterium
“Gene Gun”
Electroporation
Microinjection
Liposomes
Plant:People Interactions
• People to Plant
– Moving plants
The Good
Corn
Chile
Peanut
Apple
Potato
The Bad
Saltcedar
Tumbleweed
Kudzu
Tree of Heaven
Potato
and The Ugly
Chestnut blight
Dutch Elm Disease
Sudden Oak Death
White Pine Blister Rust
Karnal bunt
– Endangering plants– Chestnut, Echinacea
– Creating ‘new’ plants— Bt corn, RoundUp Ready
Cotton
Biotechnology Advances
• Flavr-Savr Tomato
• Ring spot virusresistant Papaya
• Golden Rice (vitamin A)
• Round-up resistant
crops (herbicide)
• BT crops (insecticide)
• ‘Designer’ plants
Genetic Engineering
• The Future:
– Antibiotics in fruits
– Salt tolerance??
#9
#8
#7
#6
#5
#4
#2
#1
– Drought tolerance??#10
– Freeze tolerance (INA)
– Mexal’s botanical kindergarten??
Plant:People Interactions
• Creating ‘new’ plants— for
the future
• Sensitive Noses: Beano-Beans
• Movie Goers:Glo-in-the-dark
Popcorn
• Indecisive New Mexicans: ‘NuMex
Red’nGreen’ Chile
• Americans: Atkins-friendly Maple
Syrup
• Christmas: Epiphany Poinsettia
• Kinder-garden: Nile water lily X
Venus fly-trap
Plant:People Interactions
• People to Plant
– Creating ‘new’ plants— for the
future
• Sensitive Noses: Beano-Beans
• Movie Goers:Glo-in-the-dark
Popcorn
• Indecisive New Mexicans:
Red’nGreen Chile
• Americans: Atkins-friendly Maple
Syrup
• Christmas: Epiphany Poinsettia
• Kinder-garden: Nile water lily X
Venus fly-trap
Sex in the Garden
Asexual Propagation
• Terms
– Cutting
– PGR (hormone)
– Sport
– Scion
– Rootstock
– Graft Union
– Tissue Culture
Sex in the Garden
Asexual Propagation
• Vegetative Propagation
– Timing (season)
– PGR
– Stem Wounding
– RH
-- Age (branch)
-- Leaf Area
-- Cutting Size
-- T
Rooting of Blue Spruce/ Wagner1987
Rooting %
Rooting %
20
45
15
40
35
10
30
5
25
0
De c
Jan
Fe b
M ar
Apr
M ay
Collection Month
20
12
15
10
10
8
5
6
0
4
5
6
7
8
9
10
11
4
Cutting Length (cm)
2
0
2000
4000
6000
8000
IBA Treatment (ppm)
10000
12
13
Genetics & Plant Breeding
• Things to Know
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DNA
Gene
Chromosome
Ploidy
• Haploid (N)
• Diploid (2N)
• Polyploid (3N, 4N, 6N)
• Things to Know
– RNA
– Mitosis
– Meiosis