Scientists are currently developing varieties of wheat resistant to a virulent fungus, which has spread from Africa to Iran. The UG99, which began in Uganda in 1999, is a strain of black rust, which can affect 80-90% of wheat crops in these countries.
Wafa Khoury, a plant pathologist at the Food and Agriculture Organisation in Rome, said the fungus was affecting crops which were once resistant. "We hope to replace affected varieties of wheat with resistant ones," she said.
Alex Waugh, director general of the National Association of British and Irish Millers, said the disease would not have any immediate impact on the UK.