"We're each other's best customer," Charles James Mayer said.

Canada buys U.S. fruit and vegetables out of season and sells beef and live cattle to the United States, he said.

"We are dependent on each other," he said.

Mayer, Canada's agriculture minister in 1993, emphasized the importance of liberalizing trade and lifting restrictions that will ultimately encourage efficient and open trade.

"We have to get rid of tariff barriers if we want to take advantage of market opportunities. Regulation stifles innovation. It hurts us as farmers," said Mayer, who retired from farming 10 years ago.

"As much as 50 percent of the world's increased food demand can be met by exports. Denying market access is almost immoral," he said.