-
Term germ plasm was first used
to describe a component of germ cell that responsible for heredity
-
There are worldwide collection
of plants, animal and bacterial germplasm for use in breeding new organism and
the conservation of existing species
Biological diversity
(Biodiversity)
-
Variability among living
organism
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Plant and animal diversity
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Terrestrial or marine
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Within species or between
species
3 aspect of
biodiversity :
-species diversity
-diversity diversity
-ecosystem diversity
Significance of
biodiversity
1.
Its is a global resource being
the underpinning factor for the healthy functioning of the earth many
ecosystem.
2.
Its provide humas with
substantial economics benefits with respect to crops, livestocks, medicine, natural
product with some 10,000 species of plants and animals exploited industrially.
3.
Its provide humans with
aesthetic benefits.
Genetic resource
application
-
Agriculture production is
increase through the use of improved genetic resource created by altering the
genetic.
Advantage:
• Increase in yield
• Pest and disease resistance
• Ecological tolerance
1.
Increase in yield
- Crops yield in rice,
wheat, barley, soybeans, cotton and sugarcane has doubled, in tomato and rubber
has tripled and in corn, sorghum, potato has quadrupled.
2. Pest &
disease resistance
- Genes responsible for
promoting resistance to 16 of these have been breed into commercial cultivars.
These genes have been sourced from wild relatives of the cultivated tomato on
which resistance at least 32 major tomato disease has been discovered.
3. Ecological
tolerance
- New varieties with
genes sourced from wild relative have been develop which are tolerant to
temperature extremes, salinity, drought, and waterlogging.
6 categories of
genetic resources:
I.
Wild relative : Species in the wild from the same genus of the crops
II.
Weedy relative : Bridge between wild relative and domesticated species evolved to
adapt the natural growing enviroment.
III.
Premitive cultivars or
landraces : The cultivated varieties during earlier
times
IV. Modern cultivars : Improved strain bred
from primitive cultivars
V.
Advanced breeding : superior germplasm selected from modern cultivars
VI. Genes from other species : advanced
lines which contain specific desired genes from other species.
Biological Diversity
Hotspots
These hotspot are the sites where many types of
biological organism exist and constitute invaluable genetic resource. They
contain :
1.
Higher range or number of
species or subspecies found in a particular area.
2.
Higher variety of life,
including the genetic diversity among members of a population or species, the
species themselves and the range of communities and ecosystem present on earth
3.
Higher variety of life form
that inhabit the earth
Genetic variation
- Source of variation : mutation and
sexual recombinant
- Mutation : Accidental changes & DNA,
rare and random
Technique to
conserve genetic resource
1.
In situ
conservation
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On site conservation e.g.,
botanical reserve, forest reserves
-
Its is the process of
protecting an endangered plant or animal species in its natural habitat
2. Ex situ
conservation
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Off sites conservation
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From threatened habitat to a
new location which may be a wild area or within the care of humans
-
Many of this crop plants can
also be clonally propagated.
Tissue culture and caryo
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