Germplasm
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...is both the genetic material
(genes, groups of genes, chromosomes)
that controls heredity and the tissues, organs,
and organisms which express variation
Contained in that genetic material
Why are genetic
resources important ?
• Introduction of new plants
• Food, fiber, medicinal or ornamental
• Changing diets: introduction of the potato
• Modification
• Plants collected in wild often have limited value per se
• We want adaptation to new environments
• Changes in size, color number of different tissues
• We want those changes to have a genetic basis
(heritable)
• Germplasm is the raw material for diversity which is the
basis for selection (plant breeding)
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Diversity in Brassica
• Hundreds of different species
• Six (6) species are cultivated
• The two most common are:
– B. oleracea
– B. rapa
Centers of Diversity
Brassica
oleracea
rapa
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B. oleracea
• Cabbage - var. capitata
- Domesticated from Kale (non-heading)
- Cultivated for medicinal purposes
- hard headed types developed about 800 AD
- Red cabbage described in 1570 in England
• Cauliflower - var. botrytis
- Evolved from broccoli
- 6th century B.C.
• Broccoli - var. italica
- Domesticated from wild cabbage
- Grown by Greeks and Romans, introduced into England 16th
century , later introduced into U.S. in early 19th century.
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The part of the plant of greatest interest to man
is the part that is modified the most. - J.R.
Harlan
Brassica oleracea
selection results in six different vegetables
Kale
Leaves
Broccoli
Flowers and stems
Cabbage
Terminal bud
Brussels sprouts
Lateral buds
Cauliflower
inflorescence
Kohrabi
Stem
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Six vegetables
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Cabbage
Kale
Brussel
sprouts
Broccoli
Kohlrabi
Cauliflower
cabbages
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For fresh
market as
savoy type
is hard to
clean
Red
Savoy
Broccoli
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• Produced in winter in Salinas
Valley of California
• Production and consumption
has tripled since 1970
• The tissue we consume is the
young inflorescence and flowering
buds. The flower primordia are
united into clusters
• Buds are functional flowers
Cauliflower
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• Consists of a dense mass
of branched floral structures
• The edible portion is a
thickened fleshy
inflorescence
• As the inflorescence ages,
there is rapid elongation. To
produce functional flowers
axillary buds are formed
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B. rapa
common members
napa
Bok-choy
Turnip
Rab
Pak Choy
B. rapa var. chinense
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• White fleshy petioles
• minimal vernalization
required for bolting
• less temperature sensitive
than Chinese cabbage,
thus, wider adaptation
Chinese cabbage
B. rapa var. pekinensis
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Non-heading Chinese cabbage 15
B. rapa var. pekinensis
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Fast Plant
• Dr. Paul Williams - UW r.
•Brassica rapa
• Flowers in 16 days
• Harvest seed in 35 days
• Plants are 10-12 cm tall
• Can be planted in a
plastic soda pop bottle
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GERMPLASM
• tissues, organs, seeds, genes, groups of genes
• any material that carries hereditary
information
The world's food supply is based on intensive agriculture,
which relies on genetic uniformity. But this uniformity
increases crop vulnerability to pests and stresses.
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Scientists need access to genetic diversity
to breed varieties that can resist pests, diseases, and
environmental stresses.
The National Plant Germplasm Service (NPGS)
aids the scientists and the need for genetic
diversity by:
• acquiring crop germplasm
• preserving crop germplasm
• evaluating crop germplasm
• documenting crop germplasm
• distributing crop germplasm
NPGS is a cooperative effort by public (State and Federal)
and private organizations to preserve the genetic diversity of
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plants.
Many important crop species originate outside the
United States
New germplasm (accessions) enter NPGS through
collection, donation by foreign cooperators or
international germplasm collections.
The germplasm is evaluated, maintained, and made
available for distribution.
You can order germplasm !
(usually free)
http://www.ars-grin.gov/index.html
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Go to Summary statistics
The Controversy:
Who owns the germplasm?
Who should benefit from research to improve a plant
species by breeding and/or genetic engineering?
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