LA GRANDE, Ore. -- When prices for Oregon's soft white wheat rose to nearly five dollars a bushel last January, farmers were beside themselves with joy.

It hadn't happened in 35 years. Now the price is twice that thanks to the collapse of a theory that has ruled global markets for decades--that somewhere in the world there would always be wheat for sale.

Bad harvests or outlooks in Australia, India, Pakistan, Texas and elsewhere have left countries who depended on reliable supplies scrambling for wheat and willing to pay top dollar.