UNDERSTANDING the genetic code of coffee could lead to better beans, researchers have said.

Scientists who sequenced the coffee genome found evidence that it evolved caffeine independently from tea and cocoa.

Dr Philippe Lashermes, a member of the team from the French Institute of Research and Development, said: "A genome sequence could be a significant step toward improving coffee."

Every day, more than 2.25 billion cups of coffee are consumed worldwide. The beverage is the chief agricultural product of many tropical countries, earning an estimated £9.38 billion in export revenue between 2009 and 2010.

A high quality draft of the genome of the coffee species Coffea canephora, which accounts for about 30 per cent of global coffee production, appears in the journal Science.

It has revealed an expanded collection of enzymes involved in making caffeine, the drug that gives coffee its zing.

But the enzyme genes were unlike those that produce caffeine in tea and cocoa. This suggests that caffeine developed independently in coffee.