The use of genetically modified crops has not led to any substantial increase in food production, Dr Hans Herren, the president of the Millenium Institute and a World Food Prize laureate said here on Thursday. Speaking at an international scientific conference in the city on ‘Can GM crops meet India’s food security and export markets?,’ Dr Herren said that even in the US, the pioneer in genetic modification of crops and one of its earliest adopters, there was only a marginal increase in the yield of 3-4 per cent, while Europe, which has not adopted the technology has registered better yield increase.