Rick Wagoner, General Motors' president and chief executive, has dismissed United Nations research that links biofuel production to rising food prices as "shockingly misinformed". The blunt assessment by the head of the world's largest car company reinvigorates intense debate about ostensible social costs and environmental benefits of biofuels, a burgeoning industry some analysts say crowds out food production. "If you look at what's causing higher [bio]fuel prices, the cost of corn is a very small part of that," Mr Wagoner said at the Auto China show in Beijing yesterday.