Plant gene treaty becomes law

Just four crops, including potatoes, account for 60% of food from plants

A global agreement to protect the planet's precious plant genetic resources has become law.

The International Treaty on Plant Genetic Resources will ensure that a huge variety of different plant species are preserved.

Keeping a rich gene pool will ensure plants varieties and genes are available to respond to global shifts, including climate change and famine.

The UN Food and Agriculture Organization says the treaty is vital.

"This treaty will ensure the conservation and availability of raw material for agriculture," FAO's Jose Esquinas-Alcazar told BBC News Online.

"Plant genes are the building blocks of new varieties," said Mr Esquinas-Alcazar, secretary of the intergovernmental commission on genetic resources for food and agriculture.

Gene code

Genes, one of the units of genetic information, determine plant characteristics, including everything from colour to resistance to certain types of disease or drought.

Mixing these genes can produce strains that are more resilient and likely to produce a better harvest.

The treaty, a quarter of a century in the making, will ensure that a vast pool of genetic resources - both in gene banks and in the field - are protected and maintained and available to all for research.

Although throughout the history of agriculture farmers have developed over 10,000 plant species for use in food production, currently only 150 crops feed almost the entire global population.

Just 12 crops - including rice, wheat, maize (corn) and potato - provide 80% of our energy from plants, according to FAO.

Lost

"At the beginning of the 20th Century in India there were 30,000 varieties of rice documented," Mr Esquinas-Alcazar said. "Today there are just 12 varieties. The others have been lost forever."

The international character of the agreement is important as countries are often dependent on each other for genetic resources in times of crisis.

In the 1970s, for example, a fungus decimated the variety of maize grown in the south of the US.

The solution, far from a chemical response, was found in a natural resistance in a variety of maize grown in Africa.