CHICAGO (Reuters) - U.S. farm groups criticized President Donald Trump’s decision to retreat from his predecessor’s opening toward Cuba, saying it could derail huge increases in farm exports that totaled $221 million last year. A trade delegation from Minnesota, one of the largest U.S. agriculture states, vowed to carry on with its planned visit to Cuba next week. “We’re going to continue to beat the drum and let them (the Trump administration) know that trade is good for agriculture,” said Kevin Paap, a farmer in the delegation. Trump signed a presidential directive on Friday rolling back parts of former President Barack Obama’s opening to the Communist-ruled country after a 2014 diplomatic breakthrough between the two former Cold War foes. Farm groups saw the move as a step backward in what had been an improving trade relationship between the two countries which are just 90 miles (145 kms) apart, even though agriculture is not directly targeted. U.S. law exempts food from a decades-old embargo on U.S. trade with Cuba, but cumbersome rules on how transactions were executed have made deals difficult and costly. Since Obama’s detente, substantial headway has been made, however, with shipments of U.S. corn and soybeans to Cuba soaring 420 percent in 2016 from a year earlier to 268,360 tonnes, U.S. Department of Agriculture data shows. Through the first four months of 2017, total shipments of U.S. grain and soy were 142,860 tonnes, up from 49,090 tonnes during the same period of 2016. While the quantities are dwarfed by total U.S. exports — nearly 56 million tonnes of corn alone last year — the added volumes were welcome as farmers face a fourth year of languishing grain prices and crimped incomes. “At a time when the farm economy is struggling, we ask our leaders in Washington not to close doors on market opportunities for American agriculture,” Wesley Spurlock, president of the National Corn Growers Association, said in a statement. The group sees an opportunity for $125 million more a year in trade to Cuba. Trump’s move could cut off near-term sales and stymie economic development that would drive longer-term demand growth, said Tom Sleight, president of the U.S. Grains Council, a grain trade development organization, in a statement. “Neither of those outcomes is favorable for the U.S. ag sector or the Cuban people,” he added. Paap said the United States should be doing more to encourage exports. “It’s frustrating because we’ve made some advances and built those relationships,” he said. 