U.S. Rep. Diane Black and former Nashville Mayor Karl Dean have the highest approval ratings in their respective gubernatorial primaries, according to a new poll from Middle Tennessee State University.

The poll, released Tuesday, found 33 percent of Republicans approved of Black, narrowly ahead of House Speaker Beth Harwell, who received 32 percent approval.

The difference between Black and Harwell fall within the poll's margin of error of error.

Knoxville entrepreneur Randy Boyd had a 28 percent approval rating. Former state Sen. Mae Beavers and Williamson County Bill Lee received 21 and 15 percent approval, respectively.

On the Democratic side, Dean's approval rating is nearly double House Minority Leader Craig Fitzhugh, who had 26 percent.

When combining the candidates from both parties together, Harwell and Dean had the highest approval ratings with 23 percent.

Black came in third with 22 percent, followed by Boyd with 17 percent.

Fitzhugh and Lee had 12 and 10 percent approval, respectively.

“Some frontrunners seem to have emerged in some of the primary races, but it’s much too early to forecast winners, even in the primaries that presently look lopsided,” Ken Blake, director of the poll at MTSU, said in a news release.

In terms of negative views of the candidates, Black led the way with 31 percent of respondents sharing a negative view of the congressman.

The negative views of Black coincide with the findings of another poll released last week by MTSU found, determined that 73 percent of respondents had a negative view of Congress.

Twenty-six percent of respondents had a negative view of Dean, followed by Beavers, who had negatives of 22 percent.

The poll did not ask whom Tennesseans plan to vote for.

The findings come after MTSU surveyed 600 registered Tennessee voters from Oct. 16-23. The poll has a margin of error plus or minus 4 percentage points.

Reach Joel Ebert at jebert@tennessean.com or 615-772-1681 and on Twitter @joelebert29.