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The Desert Legume Program: Legumes From the World's Dry Lands

Volume 2 Number 9 - December 1997

Matthew B. Johnson

The Desert Legume Program (DELEP) began in 1988 as a cooperative project of the University of Arizona College of Agriculture and the Boyce Thompson Southwestern Arboretum. Initiated by Dr R. Phillip Upchurch, the Program was established to develop a comprehensive seed bank of plants in the Legume Family (Fabaceae/Leguminosae) which are indigenous to or adaptable to dry regions of the world, to conduct on-going investigations into all aspects of these plants, and to provide samples of seeds to people and organizations working with these plants.

DELEP was established for several reasons. The Legume Family is estimated to include over 18,000 species worldwide and is often well-represented in the floras of hot dry regions. There has been no previous attempt to develop a comprehensive collection of wild species of legumes from the world's dry lands. Legumes provide many important benefits to humankind including foods, medicines, fuelwood, lumber, livestock forage, soil stabilization and improvement, and landscape plants. Vast potential exist for new, beneficial discoveries and products from these plants.

DELEP maintains a seed bank which includes approximately 1,250 identified taxa in 192 genera as of September 1997. The seeds are removed from the dried pods and stored at -18ºC to enhance longevity. Few dry land legume seeds are known to be recalcitrant. Offtakes from the seed bank have been placed in backup storage at the USDA-ARS (United States Department of Agriculture - Agriculture Research Station) National Seed Storage Laboratory in Fort Collins, Colorado. DELEP maintains a computer database containing accession information on all of the collections. This information is also available through the USDA's Genetic Resources Information Network (GRIN) database.

Samples of seeds are provided free of charge for a variety of purposes worldwide, including plants for exhibits and living collections in arboreta and botanic gardens, landscape plant evaluation, urban forestry and agroforestry, erosion control and cover crops, wildlife habitat enhancement, taxonomic research, and research into pharmaceutical compounds, insecticidal properties, and aromatic fragrances, among others. An Index Seminum is available which lists the seed bank holdings. Seeds obtained outside of the United States after 31 December 1993 are distributed following receipt of a signed agreement of non-commercialization in accordance with the intent of the Biodiversity Convention.

Woody species are maintained in research field plots in Tucson and in Yuma, Arizona to evaluate horticultural characteristics and adaptability to local conditions and to provide a source of additional seeds for the seed bank and plant material for research. Some herbaceous species are also field grown while others are maintained in containers in a greenhouse or shade house. The Taylor Family Desert Legume Garden at the Boyce Thompson Arboretum is landscaped with legumes of economic importance in dry regions. Additional legumes are maintained in the living collections of the Arboretum. In addition to two full-time staff members, the Program employs students from the University of Arizona, providing varied hands-on work experience. One of the great strengths of the Program is the dedicated group of volunteers which are actively involved in many facets of DELEP's operations, from collecting and processing seeds to greenhouse and laboratory work. An Advisory Board reviews progress and provides recommendations on current activities and future direction. A quarterly bulletin, Aridus, is distributed to over 1,100 subscribers in USA and 130 international subscribers in 37 countries.