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The Role of Botanic Gardens in the Conservation of Crop Wild Relatives

Volume 3 Number 1 - January 2006

Suzanne Sharrock

Crop wild relatives (CWR) include taxa that are closely related to species of direct socio-economic importance as well as the ancestors of modern crops.  Genes from CWR make a direct contribution to increasing the quantity and quality of our food supply and the species themselves form a vital part of both natural and agricultural ecosystems. Promoting the conservation of wild crop relatives constitutes one of the 20 agreed activities of the Food and Agriculture Organization’s Global Plan of Action for the Conservation and Sustainable Utilisation of Plant Genetic Resources for Food and Agriculture (FAO, 1996).  The conservation of crop wild relatives is an important component of the implementation of the International Agenda for Botanic Gardens in Conservation (Section 2.8) and contributes to several targets of the Global Strategy for Plant Conservation (Targets 8, 9 and 13).

Botanic gardens play a major role in the conservation of plant genetic resources. There are over 2,500 botanic gardens in existence worldwide and collectively they contain over 6 million plant accessions and an estimated 80,000 plant species (Wyse Jackson, 1999).  Many botanic gardens are playing an active role in both the in situ and ex situ conservation of crop wild relatives. 

Botanic Gardens Conservation International (BGCI) is developing a particular focus on the conservation of wild plant species.  As a partner in a GEF-funded project on the in situ conservation of crop wild relatives, BGCI is already playing a role in the conservation of crop wild relatives.  Through its extensive network of botanic garden partners, BGCI also aims to promote the long-term conservation of valuable CWR germplasm.

CWR in Botanic Garden Collections

Socio-economically important plant species include food, fodder and forage crops, medicinal plants, spices, ornamental and forestry species, as well as plants used for industrial purposes, such as oils and fibres.  Many of these species, especially medicinal and ornamental plants, are widely grown in botanic gardens and form an important part of the ex situ conservation collections of such gardens. The role that botanic gardens are playing in the conservation of wild relatives of major food crops however is less clear. This paper provides the results of an initial investigation into the conservation of wild relatives of food crops by botanic gardens.

For this survey, only those crops included in Annex 1 of the International Treaty on Plant Genetic Resources for Food and Agriculture were considered (CGRFA, 2001)(Table 1).  The Treaty, which came into force in June 2004, aims to ensure that plant genetic resources for food and agriculture, which are vital for human survival, are conserved and sustainably used and that benefits from their use are equitably and fairly distributed.  The Treaty represents a multilateral system of facilitated access and benefit sharing for the crops and forages most important for food security.  The crops listed in Annex 1 are those considered not only to be of highest value for food security but are also those for which there is a high degree of interdependence among countries with respect to their genetic diversity.

In order to carry out the survey, two main databases were consulted:

  • SINGER (System-wide Information Network for Genetic Resources) database maintained by the International Plant Genetics Resource Institute (IPGRI) (http://singer.grinfo.net/).

CWR Species in Botanic Garden Collections

A survey was carried out to identify the number of species per food crop genus recorded in botanic garden collections using BGCI’s PlantSearch database.  This database currently includes 130,000 taxa from over 600 botanic gardens worldwide.

The survey revealed that species of all 50 genera are present in botanic garden collections, and in some cases large numbers of species are recorded.  For example, 107 species of breadfruit (Artocarpus), 82 species of Lathyrus and 122 species of the Brassica complex, are listed in the database (Table 1).

A comparison was made with the number of species recorded in the SINGER (System-wide Information Network for Genetic Resources) database for the same set of species (Table 1).  It can be seen that in many cases the two databases are complementary, in that a number of genera with large numbers of species recorded in botanic garden collections, have few species recorded in the SINGER database.  Taking the examples listed above, it can be sent that SINGER includes only 5 species of Artocarpus, 46 species of Lathyrus and 33 Brassica complex species.  In other cases, many more species are recorded in SINGER than in BGCI’s database. For example BGCI records only 85 species of Ipomoea, while SINGER has 340 and records for Vigna are 12 and 88 species respectively.

It can be seen from Table 1 that botanic garden collections hold a total of 1,283 species of selected crop plants – this compares with 1,453 species listed in SINGER – a database that contains only crop data.  Given that the BGCI PlantSearch database presently holds records for only 600 or so gardens, out of the over 2,400 gardens that exist in the world, it is clear that botanic gardens are an important source of crop wild relative germplasm. 

Rare and Threatened CWR

The direct link between the BGCI PlantSearch database and the IUCN Red Lists from 1997 (Walter and Gillett, 1998) and 2004 (IUCN, 2004), allowed an analysis to be made of how many rare and threatened CWR species are included in botanic garden collections.  As shown in Table 1, according to the 1997 data, a total of 73 rare and threatened species can be identified in botanic garden collections out of a total of 593, whereas using the 2004 data (based on changed IUCN Red Listing criteria), this falls to only three species out of 65.  This reflects the relatively limited capture of data on the global conservation status of plant species post 1997. IUCN is currently addressing the need to increase the rate of Plant Red Listing and BGCI is becoming increasingly involved in this activity.  It will be important to prioritise useful plant species for Red Listing as recognised by IUCN and other partners in the Global Partnership for Plant Conservation (GPPC) (GPPC, 2005).

Table 1 - The Role of Botanic Gardens in Crop Wild Relatives Conservation
View Table 1 

Other Roles of Botanic Gardens in the Conservation of CWR

Botanic garden collections can be a useful source of plants that are of local importance, even if not listed as rare and threatened. It can be seen from Table 1 that 9 botanic gardens have yams included in special collections. These include species such as D. dumetorum, D. hispida and D. pentaphylla, species that are used in times of famine.  Other yam species found in botanic garden collections include D. floribunda and D. balcanica (a European species) that are useful sources of the steroid diosgenin – a source material for oral contraceptives.

A number of botanic gardens around the world are involved in extensive research and conservation on crop species. These include for example, the Fairchild Botanical Garden in Florida, U.S.A. which maintains an extensive collection of mango germplasm. As well as conserving mango diversity, Fairchild works to raise public awareness about this diversity through its annual mango festival and is working on the commercial development of the crop.

Other examples of botanic gardens with special crop-based programmes include:

  • The National Tropical Botanic Garden, Hawaii, U.S.A. – breadfruit collection (Artocarpus)
  • Wuhan Botanic Garden, China – kiwi conservation (Actinidia) (62 of 66 species are in China), grape – conservation and breeding
  • Jardín Botánico de Chacras de Coria, Mendoza, Argentina - wild populations of tomatoes and potatoes, Solanum ruiz-lealii, Solanum kurtzianum
  • Proyecto Jardín Botánico de la Ciudad Universitaria, Argentina – collections of Phaseolus vulgaris var. vulgaris and its wild relative P. vulgaris var. aborigineus.
  • Jardín Agrobotánico - Universidad Nacional de la Plata, Buenos Aires, Argentina - research and breeding on maize using its wild relatives

Conclusions

It is clear that botanic gardens are playing an important role in the conservation of a wide range of CWR. This includes not only the conservation of diversity, but also research and breeding to provide new crops and raising public awareness about the importance of CWR.  Botanic gardens are also important players in the overall task of conserving CWR through the horticultural and taxonomic expertise they can provide and in many cases as repositories of indigenous knowledge – especially about the crops and their relatives that grow in the locality of the garden.

References

FAO, 1996. Global Plan of Action for the Conservation and Sustainable Utilisation of Plant Genetic Resources for Food and Agriculture. [http://www.fao.org/WAICENT/FaoInfo/Agricult/AGP/AGPS/GpaEN/gpatoc.htm accessed November, 2005].

Commission on Genetic Resources for Food and Agriculture (CGRFA), 2001.   International Treaty on Plant Genetic Resources for Food and Agriculture http://www.fao.org/ag/cgrfa/itpgr.htm

GPPC, 2005.  Plants2010. [http://www.plants2010.org/, accessed, November, 2005]
IUCN, 2004.  2004 IUCN Red List of Threatened Species http://www.redlist.org/

Mabberley, D.J., 1997.  The plant-book. 2nd ed. CUP, Cambridge, U.K.

Walter, K.S. and Gillett, H.J. (eds.) 1998. 1997 IUCN Red List of threatened plants. Compiled by the World Conservation Monitoring Centre. IUCN - The World Conservation Union, Gland, Switzerland & Cambridge, UK.

Wyse Jackson, P.S. (1999) Experimentation on a Large Scale- An Analysis of the Holdings and Resources of Botanic Gardens.  BGCNews 3(3):27-30.