Abstract—Crop genetic resources
are essential for agricultural production, and their use results
in significant economic benefits. But conservation of crop genetic
resources is complicated by their public goods attributes.
Agriculture's Dependence on Genetic Resources
Agriculture and genetic resources are critically interdependent.
All agricultural commodities, even modern varieties, descend from
an array of wild and improved genetic resources from around the
world. Furthermore, agricultural production depends on continuing
infusions of genetic resources for yield stability and growth.
Genetic improvements have arisen in several ways. Before the development
of modern varieties, farmers cultivated landraces. Landraces
are varieties of crops that evolved and were improved by farmers
over many generations. The pace of crop improvement accelerated
as modern breeding techniques were developed that facilitated selection
of specific desirable traits. Breeders have crossed different parental
material and selected traits resulting in higher yields, quality
changes, and desirable production traits.
Breeders have also sought resistance to pests and diseases, and
tolerance to nonbiological stresses such as drought. Because pests
and diseases evolve, breeders continually need new and diverse germplasm
from outside the utilized stock, sometimes using wild relatives
of cultivated crops and landraces, to find specific traits to maintain
or improve yields (Duvick, 1986). USDA has estimated that new varieties
are resistant for an average of 5 years, while it generally takes
8-11 years to breed new varieties (USDA, 1990). Plant breeders often
rely on landraces or wild relatives as a last resort, because often
it is more difficult to incorporate genetic material directly from
these sources. Undesirable traits often accompany the trait of interest,
and extensive breeding may be needed to produce a final variety.
However, when used, genes from these materials have "often
had a disproportionately large and beneficial impact on crop production"
(Wilkes, 1991).
Economic Values of Genetic Resources
Attaching a value to genetic resources is hard; describing their
benefits is easier (Day-Rubenstein et al., 2005). The simplest value
arises from the "direct use" of genetic resources to
produce food and fiber or to help create new varieties of crops.
Conserved genetic resources may also have economic value even if
they are not being used at the time. The option to exploit resources
in the future, for uses not presently known, has considerable value,
though this value is difficult to measure. Also, the information
about a conserved resource has economic worth. For example, the
fact that a species of potato occurring naturally in the Andes has
genes adapted for high altitudes may guide breeders toward a set
of related germplasm in the future.
Modern molecular biology techniques such as genomics hold promise
for reducing the costs of searching for useful traits in conserved
material, therefore increasing its value. At present, however, much
work would be required to turn raw genetic sequence data into useful
information (Attwood, 2000), and neither sequence data nor resources
for sequencing are now available for landraces or wild relatives.
Various economic methods have been used to value genetic material,
but isolating the contribution made by genetic resources is difficult.
Breeders use the genetic material to create new varieties, but the
research effort by breeders has value as well.
Thus, many studies have focused on the value of "genetic enhancement,"
or the value arising from the use of genetic material by
breeders.
For example, the Office of Technology Assessment (1987) estimated
that genetic improvements have accounted for half the yield gains
in major cereal crops since the 1930s. Thirtle (1985) estimated
the contributions of biological advances to U.S. crop production,
controlling for changes in other inputs such as fertilizers, machinery,
and pesticides, and concluded that biological improvements contributed
to 50 percent of the yield growth of corn, 85 percent for soybeans,
75 percent for wheat, and 24 percent for cotton. Duvick (2005) estimated
that 50 percent of the increases in maize (corn) yields since the
early 1930s have been due to breeding. To date, practically all
published economic analyses of the collection of genetic material,
conservation in gene banks, or use of genetic resources in plant
breeding programs have shown significant economic benefits from
these activities.
Besides estimating the total value of genetic improvements, it
is also possible to estimate the distribution of these benefits.
ERS researchers estimated the value of improved crop varieties by
modeling the difference in economic welfare for both consumers and
producers (crop and livestock) had there not been crop improvements
in five major U.S. crops. U.S. producers generally gain as lower
production costs outweigh the losses from lower commodity prices.
Producer gains are estimated at over $160 million annually. Lower
prices benefit consumers by an estimated $223 million per year.
Together, the net economic effect from genetic enhancements is estimated
at roughly $385 million per year. Economic welfare also rises worldwide.
Consumer benefits from lower food prices outweigh producer losses,
leading to net welfare gains estimated to exceed $600 million per
year (table 3.1.1).
Table
3.1.1—Estimates of annual benefits from genetic enhancements
in U.S. major crops
Region
Change
in
producer
benefits
Change
in
consumer
benefits
Total
welfare
change
$
Million
United
States
162
223
385
Canada
-17
18
1
European
Union
-103
180
77
Other
Western Europe
-10
16
6
Japan
-9
66
57
Australia/New
Zealand
-14
8
-6
China/transitional
economies
-171
210
39
Developing
agricultural exporters
-61
62
1
Developing
Asian importers
-5
14
9
Rest
of world
-119
157
38
Total
-347
954
607
Source: Based on methodology
used in Frisvold et al., 2003.
Genetic Diversity
The loss of genetic diversity in a species, also called genetic
erosion, has been identified in many commercially important crops.
One reason for this decline in diversity has been the loss of landraces
and wild relatives of cultivated crops. The loss of wild relatives
occurs mainly through habitat conversion. Because the economic values
of wild relatives can rarely be appropriated (i.e., captured) by
landowners, they may have less incentive to preserve habitats for
wild relatives than to devote land to alternative uses such as clearing
for agricultural or urban use.
Genetic erosion of crop varieties can be hastened as landraces
are displaced by commercially developed varieties. Farmers want
high yield potential and desirable consumption attributes, and commercial
varieties are often superior in these respects. While maintaining
a diverse set of landraces may benefit plant breeding, individual
farmers are unlikely to account for this when selecting seed. Landraces,
though, become extinct if farmers stop planting and maintaining
them.
Widespread adoption of genetically uniform crop varieties makes
the crop population more susceptible to a widespread disease or
pest infestation. Genetically uniform varieties may initially be
more resistant to pests and diseases. But as pests and diseases
evolve to overcome host plant resistance, genetic uniformity increases
the likelihood that such a mutation will prove harmful to a crop;
disease could affect newly vulnerable varieties accounting for a
greater proportion of a crop's production. Genetic uniformity
contributed to the spread of the Southern corn leaf blight, which
reduced the U.S. corn crop by 15 percent in 1970. Since then, the
genetic vulnerability of wheat and corn is thought to have lessened
(in part because of efforts to breed in greater diversity), but
the genetic uniformity of rice, beans, and many minor crops is still
a concern (NRC, 1993; FAO, 1998).
Despite concerns that crop yields and production will become more
variable (Swanson, 1996), yields for many major crops have been
relatively stable. This is probably because temporal diversity (diversity
through time) has replaced spatial diversity (diversity across an
area) (Duvick, 1984). Modern plant breeding provides a steady release
of new varieties with new traits for pest or disease resistance.
Keeping ahead of pests and diseases through temporal diversity depends
on the quality of germplasm in public gene banks and in private
breeder collections. Many of the benefits of raw germplasm cannot
be appropriated because genetic material has public good characteristics.
As a result, private breeders rely on the public sector to collect,
characterize, and perform pre-breeding enhancement of genetic materials
to make them available for private use (Duvick, 1991).
Tools To Conserve Genetic Resources—In Situ
Most of the world's genetic diversity is found in situ.
Species preserved in situ remain in their natural habitat.
For agriculturally important species, the greatest diversity in
landraces and in wild relatives may be found near their centers
of origin, i.e., the places in which they were first domesticated
(fig. 3.1.1). In situ preservation efforts, as well as
germplasm collection activities for ex situ conservation,
are often focused on centers of origin.
Because in situ conservation of agricultural genetic resources
is carried out within the ecosystems of farmers' fields or wildlands,
species continue to evolve with changing environmental conditions.
In situ preservation can provide valuable knowledge about
a species' development and evolutionary processes, as well as how
species interact (table 3.1.2).
Table
3.1.2—Advantages and Disadvantages of in situ and ex
situ conservation
In
Situ conservation
Ex
Situ conservation
Advantages
Disadvantages
Advantages
Disadvantages
Genetic
resources used
to produce valuable
product
Costs
borne by farmers
Costs
generally
centralized
Certain
types of
germplasm not readily
conserved
Evolutionary
processes
continue
May
reduce farm
productivity
Can
preserve large
amounts of diverse
germplasm
Regeneration
can be
costly, time-consuming
May
better meet the
needs of certain
farms
Requires
land
Germplasm
can be
more readily accessed
by more breeders
Potential
for genetic
"drift" can reduce
integrity of collection
More
efficient for some
germplasm, e.g.,
animals, crops that
reproduce vegetatively
Farmer
selections may
not preserve targeted
diversity
High-security
storage
impervious to most
natural disasters
In
practice, many
collections are
insufficiently funded,
organized, and
documented
Existing
wild relatives
can be preserved
without collection
In situ conservation of biodiversity is not more widely
practiced because the private costs of doing so often outweigh the
private benefits. Many decisions that affect conservation of biodiversity,
such as choice of variety or deciding whether to clear land, are
made at the individual or local level. To preserve agricultural
genetic diversity in situ, a farmer may have to forgo a
more profitable variety. For wild in situ resources, the
land may need to be set aside completely.
It is difficult for countries—let alone individual farmers—to
capture all of the value from genetic resources. Markets do not
exist for most of the other environmental services provided by biological
resources, such as benefits provided for wildlife species, and certain
genetic resources are easy to transport and replicate.
Developing countries, where many in situ genetic resources
for major crops are found, often face greater pressures for wildland
conversion because of population growth and extensive farming techniques.
In contrast, the quantity of agricultural land in the developed world
has remained relatively stable or declined.
Tools To Conserve Genetic Resources—Ex Situ
The ex situ method of genetic resource conservation removes
genetic material from its environment for long-term conservation,
most often in gene banks. The world's gene banks presently hold
more than 4 million accessions, or specific samples of crop varieties.
However, crop genetic resources must be collected, and only a
fraction of the world's germplasm has been collected thus far. Stored
plant materials must be kept under controlled conditions, and periodically
regenerated (planted and grown) in order to maintain seed viability
(table 3.1.2). Not all kinds of plant genetic resources are easily
conserved ex situ: some plants may need to be kept as living
plants, a more costly process that requires additional land and
labor. The resources necessary to maintain plant gene banks also
face competing demands from other public programs.
U.S. Policies To Protect Genetic Resources
The United States promotes the conservation and use of genetic resources
by (1) funding germplasm preservation efforts here and abroad and
(2) pursuing international agreements. U.S. plant preservation is
led by the National Plant
Germplasm System (NPGS), which is administered by USDA's
Agricultural Research Service. The NPGS, which houses more than
10,000 species, including wild relatives of crops, is one of the
world's largest collectors and distributors of germplasm.
It focuses on germplasm that may be needed by both public and private
breeders, now and in the long term (see box). Private incentives
to collect and maintain such a collection are small, because any
economic returns may not be realized until well into the future.
Likewise, collecting exotic germplasm such as landraces and wild
relatives can be expensive. However, it is a crucial source of needed
traits, particularly resistance traits.
Box: Types of Germplasm
Germplasm can be categorized into three basic types:
(1) elite or modern, (2) landraces, and (3) wild and
weedy relatives. Elite or modern germplasm has been
improved by plant breeders. It may be a final cultivar
(either recently developed or obsolete), or it may
be germplasm that has been modified by a breeder for
use in creating cultivars. Because landraces and wild
or weedy relatives often contain unique traits, they
increase the diversity of a germplasm collection.
At the same time, elite material also contains diverse
genes, which may be less exotic, but are generally
easier to use (NRC, 1993). Thus, curators and breeders
typically will want all three types of germplasm in
a collection. In addition to these three basic types,
germplasm collections also may include "genetic
stocks," mutants and other germplasm with chromosomal
abnormalities that are used by breeders.
A recent study by the U.S. General Accounting Office found that
relatively few wild relatives of domesticated varieties are held
in gene banks, and not all collections have sufficient diversity
(table 3.1.3). Gene banks also may not be receiving adequate funding
to fulfill their mission (Day, 1997). For example, the NPGS lacks
sufficient funding to complete evaluation and documentation of its
samples, or to perform necessary backups and regeneration of seed
accessions (GAO, 1997).
Table
3.1.3—Some germplasm collections with insufficient diversity
for reducing crop vulnerability
Collections
with insufficient diversity to reduce crop vulnerability:
Grapes
Cool-season
food legumes
Sweet
potatoes
Cucurbits
(e.g., cucumbers, squash, and pumpkins)
Tropical
fruit and nuts
Walnuts
Prunus
(peach and cherry trees)
Herbaceous
ornamentals
Woody
ornamentals
Germplasm types with insufficient diversity:
Wild
and weedy relatives: almost 50%, including corn and soybeans.
Landraces:
12 out of 40 collections, including corn, wheat, cotton,
and alfalfa
Genetic
stocks: 50%, including alfalfa, peanuts, grapes
Obsolete
and current cultivars: 5 out of 40 collections
Source: GAO, 1997.
International Policies on Genetic Resources
Most U.S. farmers produce non-native crops and livestock (NRC, 1993).
Access to genetic resources in other countries is therefore critical
to maintaining the rate of varietal improvement. Almost every plant
species of major economic importance to the United States has been
improved with germplasm from elsewhere. Past collection efforts
and extensive breeding activities have resulted in the United States'
actually being a net supplier of plant germplasm to the rest of
the world (fig. 3.1.2). The NPGS supplies germplasm, free of charge,
to anyone who requests it. Still, the United States continues to
rely on other countries for genetic material. So, international
agreements that affect the exchange of germplasm are an important
tool for both U.S. policymakers and genetic resource managers.
The U.N. Convention on Biological Diversity (CBD), which came into
force in 1993, is the most prominent international agreement addressing
preservation of genetic resources. Historically, genetic material
was regarded as the common heritage of humankind. Developing countries,
the centers of origin for many crops, have often provided raw genetic
material to public germplasm repositories.
Whether forgone earnings from raw genetic material are compensated
for by free access to public genebanks and lower world food prices
is an open question (Shands and Stoner, 1997; Fowler, 1991). But
the traditional "free flow" of "unimproved"
genetic resources and landraces between countries is no longer a
given. The CBD is the most well-known in a serious of multilateral
agreements to address (among other issues) ongoing disputes over
the exchange and use of plant genetic resources. President Clinton
signed the Convention in June 1993, but the U.S. Senate has not
ratified it yet. The United States attends meetings as a non-voting
observer.
In addition to the CBD, the International Treaty on Plant Genetic
Resources for Food and Agriculture (IT) came into force in 2004.
For parties to the treaty, the IT governs the international
exchange of germplasm for specified crops, including wheat, maize,
rice, and alfalfa (though not other important crops such as soybeans,
tomatoes, and peanuts). It is also intended as a mechanism to
fund genetic resource conservation. In June 2006, the governing
body adopted a Standard Material Transfer Agreement that defines
the terms of germplasm exchange for covered crops. As a result,
U.S. policymakers and genetic resource managers face new exchange
terms and rules governing benefit sharing, even though the United
States has not ratified the IT. Uncertainties still surround the
valuation of crop genetic resources and the sharing of benefits
from germplasm preservation and exchange. Whether funds will be
adequate for the preservation provisions of the treaty are also
unclear.
The expansion of intellectual property rights may further affect
genetic resource conservation and exchange. The CBD and IT establish
property rights for plant germplasm in countries that are parties
to the treaties, but the effects of these provisions on conservation
have not yet been observed.
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