From: owner-sard-room3
To: sard-room3
Subject: Abstact of Paper by A. B. Damania
Date: Wednesday, November 01, 1995 2:37PM

IN SITU CONSERVATION OF GENETIC RESOURCES, WITH SPECIAL REFERENCE 

TO WILD PROGENITORS OF WHEAT

ARDESHIR B. DAMANIA, Genetic Resources Conservation Program,
University of California, Davis, CA 95616-8602, USA

Email: abdamania@ucdavs.edu 

ABSTRACT

The depletion of crop plant genetic resources in their centers of
diversity can be associated with the spread of modern agricultural
practices. These include the adoption of improved higher yielding
genetically uniform varieties requiring high inputs over large
areas resulting in the abandonment of the genetically variable,
indigenous varieties grown by subsistence and other farmers.

As a result of considerable rise in collection and conservation
activity of crop plant genetic resources during the last two to
three decades a very large quantity of germplasm accessions of
cultivated, obsolete/primitive and wild forms of crop plants have
been assembled and stored ex situ at various genetic resources
conservation centers around the world. Ex situ conservation is
conservation outside the natural habitat. In crop plants, this is
the form of samples of seeds, tissue cultures, or complete plants
in orchards, etc. Although ex situ methods, such as gene banks and
botanical gardens, have contributed to the improvement of certain
plants and major food crops, such as wheat, through utilization of
preserved germplasm they do not provide a panacea for conserving
naturally occurring genetic resources and protection of the
habitat, and hence in situ methods remain the single most effective
means of conserving diversity. Also, agricultural crop diversity
cannot be preserved without saving the farm community.

To overcome the limitations of the ex situ collections,
preservation of crop wild relatives populations in their natural
habitat is important for long-term benefits of national programs
and the international community as a whole. In situ preservation
projects for the conservation of populations of the wild
progenitors of wheat have been started in Israel and in Syria. The
germplasm so conserved will be adequate not only for fulfilling
current research needs but also those for the future, such as
responding to changed climatic conditions due to global warming
(the so called 'greenhouse effect'), changing rainfall patterns,
acid rain and habitat destruction.

In situ methods of conservation of landraces and wild progenitors
are, understandably, looked at with skepticism by plant breeders.
As long as genetic conservation and crop improvement are directly
linked, any form of conservation will be judged by its short-term
benefits to breeders, and in situ methods will attract considerable
opposition. However, on-site conservation is more plausible if
these two goals are decoupled, making biodiversity conservation an
end in its own right.

There are some islands in the Mediterranean sea which are
out-of-bounds for all except the Italian navy who visit them
sporadically. It has been suggested bysome conservationists that
these islands be used to establish nature reserve parks where it
would be easy for in situ conservation to proceed undisturbed by
human factors. Also, there would be no import or export of genes to
and from such islands and a degree of equilibrium in the genetic
structure of the conserved species could become established with
time.

To ensure success of in situ conservation activities involving crop
plants, needs and demands of local farmers must be identified and
satisfied in concert with preservation endeavors and developed as
an integral part of land-use management. Human population pressures
and the need for increased food production will restrict the
success of strict conservation management practices when it is
perceived that little or no economic benefits are forthcoming from
these efforts. 

The distribution pattern of the genetic diversity and human
activities at or near the site will in turn determine optimal
conditions in suitable locations for in situ conservation of the
target species. In several cases in situ conservation may actually
be less expensive than ex situ maintenance of collections,
especially if methods other than direct financial subsidies to
farmers are implemented.

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