Medicago truncatula Germplasm Collection

---

Introduction The Medicago truncatula collection is a part of the National Plant Germplasm System (NPGS). Seed is freely available to support research and breeding objectives around the world.
Collection Origin We received the first Medicago truncatula accession in 1950, when a commercial strain and 9 unimproved samples were received from J.R.A. McMillan from the University of Sydney, New South Wales, Australia. Currently the collection includes 324 ecotypes of M. truncatula, originating from 22 countries. Search the Germplasm Resources Information Network (GRIN) for further details
on the collection. Over 50 % of the accessions were collected in Algeria, Morocco and Tunisia. A collaborative collection was made in 1973 in Morocco by I. Forbes, from the USDA, ARS, Georgia, USA, and J.S. Gladstones, from the Department of Agriculture, South Perth, Australia. W. Graves, from the University of California, California, USA, made extensive collections in Morocco and Tunisia in the early 1980s. Approximately 55 % of the collection was received in the late 1980’s, when the NPGS inherited the germplasm collection of the late Canadian taxonomist, Dr. Karl A. Lesins. Most of the accessions (80 % of collection total) in the M. truncatula collection are unimproved or wild germplasm. 15 % of the collection is either cultivars or breeding material. A large portion of the cultivated germplasm has been obtained from Australia. We are actively working to expand the collection to include important genetic stocks that are being developed by the genomics community.
Storage and Regeneration The collection is housed and distributed from the Western Regional Plant Introduction Station located in Pullman, Washington. Our mission is to maintain the genetic diversity inherent in our collected germplasm. Although most of the annual medic species are self-pollinated, they are surprisingly heterogeneous, and we treat them as populations. Distribution seed lots are stored at 4 ° C and 30 % relative humidity. Original and regeneration seed lots are stored at - 10 ° C. The germplasm is increased at the National Temperate Forage
Legume Germplasm Resources Unit, in Prosser, Washington. Transplants are started in the greenhouse each spring. To minimize genetic change during seed increase, 50-100 individual plants are used. Although M. truncatula is a self-pollinated species, we isolate individual accessions in cages, since a small but genetically significant level of cross pollination has been reported.
Characterization Characterization and evaluation are an important part of our work. In 2003, we carried out an extensive morphological evaluation of the entire M. truncatula collection. Our objectives were to characterize the length of growth stages, as well as
the morphological features of leaves, branches, flowers and fruit for each accession. You can examine and download evaluation data from GRIN.
Ordering Germplasm Interested in obtaining seed? Contact Dr. Stephanie Greene, Medicago curator; or request germplasm online using GRIN ONLINE ORDER (http://www.ars-grin.gov/npgs/orders.html).