Corn prices jumped to a record $6 a bushel Thursday, driven up by an expected supply shortfall that will only add to Americans’ growing grocery bill and further squeeze struggling ethanol producers.

Corn prices have shot up nearly 30 percent this year amid dwindling stockpiles and surging demand for the grain used to feed livestock and make alternative fuels, including ethanol.

Prices are poised to go even higher after the U.S. government this week predicted that American farmers – the world’s biggest corn producers – will plant less of the crop this year. The U.S. Department of Agriculture projected that farmers will plant 86 million acres of corn in 2008, an 8 percent drop from last year.

Worldwide demand for corn to feed livestock and to make biofuel is putting enormous pressure on global supply. With the U.S. expected to plant less corn, the supply shortage will only worsen.