Mexico, the world's biggest buyer of US corn, is considering offering duty-free access to Brazilian or Argentine maize as an alternative to American imports in a move that could have big consequences for US farmers worried about President Donald Trump's trade and tax agenda. Mexico currently imports 98 per cent of its corn from the US and total US farm sales to Mexico were $17.7 billion last year - five times greater than when the North American Free Trade Agreement came into force in 1994. Mexican corn imports from the US were worth $2.3 billion in 2015, according to the US Department of Agriculture,