[RIO DE JANEIRO] A Brazilian gene bank of plant seeds has become the world's seventh largest, behind banks in United States, China, Germany, Japan, India and South Korea.

Gene banks store genetic material from plants or animals — such as seeds, spores or eggs — frozen in cold chambers at minus 20 degrees Celsius, keeping it intact for over 100 years for later use.

Last week, the number of seed samples stored in the gene bank managed by the Brazilian Agricultural Research Corporation (Embrapa) reached 102,000, representing genetic material collected from 500 different plant species.

Magaly Wetzel, a coordinating manager of the 30-year-old gene bank, said that conserving a rich variety of seeds is essential for a country with a strong agribusiness sector like Brazil.

"The seeds provide a wide range of genes that can be used to develop more suitable crops for every Brazilian region. With genetic improvement it's possible to originate plants with resistance to diseases or to dryness," said Wetzel, who is a researcher at the Genetic Resources and Biotechnology Unit of Embrapa.

Gene banks can also help prevent species extinction. If the seeds are stored, plants that no longer sprout naturally can be reintegrated into agriculture.

This has been done by several indigenous communities — such as the Krahô, Guarani and Indian tribes from the Xingu river basin in Brazil — that approached Embrapa asking for primitive plants seeds that no longer germinate. The species were important not only to their agricultural system but also to their cultural rituals.

Samples with commercial value — especially soybean, rice, beans and corn — are conserved, as well as primitive ones like cotton and cassava.

Wetzel says four new cold chambers will open this month, doubling the bank's capacity to 240,000 samples.

"Now we have to work to fill them. Agriculture sustains men, but only genetic resources can ensure a sustainable agriculture," she told SciDev.Net.

New seeds are constantly added to the bank from international exchanges and field collections. Regular tests evaluate their germination ability.

The world's largest seed bank is managed by the Agriculture Research Service of the United States Department of Agriculture. It holds more than 460,000 seed samples and has the capacity to store up to 1 million.