More than 7 million seed samples are stored at about 1,750 banks scattered around the world; a great contrast compared with the 1970s, when only a dozen centres existed.

"To continue producing the food we need we have to improve our varieties" at a time when the climate, the forms of production or consumer tastes are changing, says FAO expert Francisco López.

While people have traditionally exchanged seeds, depopulation of the countryside, the industrialization of agriculture and other modern phenomena have made this task more difficult.

The specialist of the secretariat on the International Treaty on Plant Genetic Resources for Food and Agriculture explains that, given the alarming loss of diversity, it becomes necessary to go to the places where those varieties come from and look for their wild relatives.

"Germplasm (seeds) banks have the task of collecting, preserving and documenting the material, as well as making the data available to anyone," he points out, recalling that most of the preservation continues to be done by the growers themselves in the field.

Versatile seeds 
What is mostly sought now in seeds is versatility; being able to resist pests, water shortages or high salinity.

But to achieve their adaptation they first need to be preserved. López stresses that this "is really complex work" and involves the organization of missions to collect materials, being aware of what's already in storage and comparing it with other collections with the goal of mapping a crop's diversity.

Sometimes, the lack of resources makes it impossible to keep the seeds in good condition. In addition to funding, the duplication of plant material carried out by researchers around the world is also essential.

In fact, the 135 countries which have so far signed the international treaty on plant genetic resources (in force since 2004) have agreed to exchange 64 varieties of major crops for food and agriculture.

This way, scientists can request material stored in seed banks by means of a standard contract; in fact, 2.6 million transfers of samples have been carried out since January 2007, according to FAO data.

Within this system, the centre of Svalbard, Norway, works in an exceptional way.

In this archipelago near the North Pole, in a sort of bunker dug beneath the ice, we find the world's largest seed bank, with more than 860,000 samples.

It is actually a backup of the material sent from different seed banks or countries, which are the only ones who can recover what is actually theirs.

The director of this centre, Roland von Bothmer, stressed that Svalbard offers stable conditions, including a permanent, natural cold, to maintain the seeds, regardless of power failures, financial problems, extreme natural phenomena or conflicts in other parts of the planet.

From Syria to Norway
Given these difficulties, Von Bothmer praises the work of the employees of the seed bank located on the outskirts of the Syrian city of Aleppo. Despite the war, they managed to transfer around 90% of the material they stored to Svalbard.

"We are ready to send them the material as soon as they request it," he assures.

Three times a year, Svalbard's doors open to welcome new material, which is then registered, labelled and stored in boxes. It is a long journey for many seeds, many of which are unique and a natural treasure worth preserving.