Agriculture Reference
In-Depth Information
TABLE 14.3
Genetic Resources and Processes of Importance in Sustainable Agriculture
Resource or Process
Advantage for Sustainability
Broad genetic base in the form of many landraces and
developed varieties
Reduces genetic vulnerability; allows continued production of
genetic variation
Variable gene frequency within and among landraces
Reduces genetic vulnerability
Gene flow within and between landraces, occasionally
from wild relatives
Maintains variability, diversity, and environmental resistance
Selection for diversity of local adaptations
Maintains local flexibility in environmental resistance
Relatively small populations
Promotes diversity due to genetic drift
Open pollination breeding systems
Promotes outcrossing; maintains variability
Longer life cycles
Promotes outcrossing
Regional, patchy distribution
Promotes diversity
Presence of wild relatives
Can lead to spontaneous hybrids and variation
Local breeding
Promotes diversity and adaptability; maintains environmental
resistance
Flexible and diverse environmental conditions on the farm
(e.g., intercropping)
Provides microsites for retention of variable genetic lines
High overall diversity in the agroecosystem
Allows for interaction and development of more complex
interdependencies and coevolution
Source
: Adapted from Salick J, and Merrick LC. In C. R. Carroll, J. H. Vandermeer, and P. M. Rosset (eds.),
Agroecology
.
pp. 517-548. McGraw-Hill: New York. 1990.
efforts so that they work with all the multiple levels of the
farm system. We need to reduce vulnerability and depen-
dence on human interference through a strategy of diver-
sifying the agricultural landscape, the crop species in agro-
ecosystems, the varietal composition within species, and
the resistance mechanisms within varieties. Otherwise, we
end up stuck on the crop breeder's treadmill, trying to stay
a short step ahead of the problems created by the very
systems we have designed.
INTERNET RESOURCES
Biological Diversity in Food and Agriculture
http://www.fao.org/biodiversity
The agrobiodiversity section of the United
Nations' Food and Agriculture Organization
site. A portal to a great deal of information
and data about agrobiodiversity.
Center for Food Safety
www.centerforfoodsafety.org
This organization's site has a great deal of good
information related to the hazards of geneti-
cally engineered crops.
FOOD FOR THOUGHT
1.
What are the similarities and differences
between an obligate mutualism in a natural eco-
system and the relationship between humans
and their domesticated organisms?
International Plant Genetics Resources Institute
www.ipgri.cgiar.org
The world's largest nonprofit agricultural research
and training organization devoted to promoting
agrobiodiversity.
2.
What can we learn from traditional farming
systems in developing countries about applying
directed selection in a way that promotes
sustainability?
Native Seeds/SEARCH
www.nativeseeds.org
This organization works to preserve the many
locally adapted plant varieties used by indig-
enous groups in the Americas.
3.
What are the weaknesses of a germplasm pres-
ervation program that focuses only on the key
crops and the storing of genetic material in large
environmentally controlled germplasm banks
isolated from the field situation?
People and Plants International
www.peopleandplants.org
An organization devoted to sustainable resource
management, and focused on the preserva-
tion of plant biodiversity worldwide.
4.
How do your own personal choices at the
market exert pressure on the selection of the
genetic material used by farmers?
5.
What is meant by “agroecosystem selection” in
the directed selection process?
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