(CNN) Former Arkansas Gov. Mike Huckabee resigned Thursday from the Country Music Association Foundation board of directors -- less than one day after his appointment -- after backlash over his anti-gay rights record.

"I genuinely regret that some in the industry were so outraged by my appointment that they bullied the CMA and the Foundation with economic threats and vowed to withhold support for the programs for students if I remained," Huckabee wrote in his letter of resignation

Huckabee didn't mention the controversy over his stance on gay rights in his letter. But he wrote, "If the industry doesn't want people of faith or who hold conservative and traditional political views to buy tickets and music, they should be forthcoming and say it."

A message left by CNN with the foundation seeking comment Friday morning was not immediately returned.

Huckabee, a two-time Republican presidential candidate, compared legalizing same-sex marriage to incest and polygamy in 2010. He also compared same-sex adoption to experimentation, saying that "children are not puppies."

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