The hottest summer since record-keeping began 130 years ago has cost Russia more than a third of its wheat crop, and prompted the government to ban wheat exports.

Ivan Obolentsev, head of the Agro-Industrial Union, says the country's top priority is to meet the domestic demand for grain, even if this means foregoing Russia's hard-earned place on the international grain market. Officials say crops have been adversely affected by hot weather and lack of rains this year, with the expected yield cut by half.

Russian Prime Minister Vladimir Putin said last week the wheat export ban would last through the end of the year.