The UPM Seed Bank in Madrid (Spain)
Volume 2 Number 9 - December 1997
Prof. César Gómez-Campo
The seed bank of the Universidad Politécnica de Madrid (UPM) was created in 1966 and has pioneered seed banking of wild species. Its aim is the long-term ex situ conservation of wild taxa and supply of seed material for basic or applied research. Emphasis is placed on the crucifer family and, since 1973, on rare and endangered species of any family growing in the western Mediterranean area. The catalogue includes 600 crucifer accessions and rare and endangered species. Members of the tribe Brassiceae - to which most economically important crucifer genera belong (Brassica, Raphanus, Sinapis, Eruca, etc.) - are well represented. In 1982, IBPGR (now IPGRI) designated the bank as the world base collections of wild crucifers. Thousands of samples have been dispatched to many interested individuals or working groups which has significantly stimulated research in this field.
Between 1982 and 1988, a plan to rescue Mediterranean populations of eight wild Brassica species with a chromosome number of n=9 (including Atlantic B. oleracea) was put into practice by an international team. 250 samples were stored as a base collection, and some new accessions have been subsequently incorporated. A multiplication programme was also succesfully undertaken.
Collection of endemic species is the first priority in ex situ conservation of rare and endangered species. Seeds are often collected by local botanists who are familiar with local endemics (project "Artemis"). Although the richness of the west Mediterranean flora makes this task very difficult, approximately 60% of the Spanish flora is now preserved by this method. At least one species - Diplotaxis siettiana, from Alborán Island (south of Spain) - has been saved from extinction by reintroduction after its unique population disappeared from nature. The development of a net of similar seed banks after 1980 in Spanish botanic gardens (Cordóba, Las Palmas, Sóller, Madrid, Blanes) has meant duplicates can be stored. Distribution of this material is limited, since the main objective is conservation.
The procedure of seed preservation consists of placing the seed samples within sealed glass ampoules with silica gel inside. A seed moisture content of between 3 and 4% is achieved and maintained. This is supplemented by storage in a cold room at -10ºC. The air tightness of the containers and the use of silica gel to continuously monitor the humidity, are considered the two basic pillars for any long-term seed preservation project. In the case of the UPM Seed Bank, germination tests conducted after 25 years, have shown the efficiency of this ultra-dry method. In fact, most seed samples tested showed increased germination percentages, probably due to the existance of some initial dormancy.