JACKSON (AP) — Gov. Phil Bryant wants to end Mississippi’s statewide system of seniority-based teacher raises. Instead, the Republican governor wants each of the state’s 151 school districts to design their own system to pay teachers according to student performance.

Bryant released a merit pay report from Mississippi State University researchers at a Friday news conference. The report suggests basing merit pay on Mississippi’s new teacher evaluation system, which is slowly being rolled out.

“It is time we start paying teachers for quality, not just longevity,” Bryant said.

Leaders of two teachers’ unions said they’d need more details, but were initially cool to the idea.

Kevin Gilbert, of the Mississippi Association of Educators, said any discussion needs to include raising overall teacher pay, not just redistributing it. Mississippi’s average teacher pay in 2011 was $42,307, second lowest behind only South Dakota, according to the National Education Association. The national average was $55,241.

Mississippi teachers are now paid based on what degree they hold and how many years they’ve been working. A teacher with a bachelor’s degree starts out at $30,900 and gets a $495 raise every year, all the way up to $50,285 after 35 years. Those with graduate degrees get paid more and get larger yearly raises.

Many local systems use their own tax revenue to raise salaries.

The governor said good teachers should be rewarded for high performance, and said cash rewards will encourage teachers to improve.

“In the real world, you improve because there is a reason to do so,” Bryant said.

Studies, though, have been mixed on whether test scores increase when teachers get paid for performance. A new study of teachers in an Illinois district finds that it does, while other recent studies have found small or no benefit.

A merit pay system is probably years away in Mississippi, because the statewide evaluation system is in its infancy. The state is still recruiting districts to pilot the teacher evaluation system next school year and the Department of Education plans to examine results and do another year of field testing. A statewide rollout is planned in 2014-2014.

Half of a teacher’s grade under the system would be based on how much their students learn that year, as measured by tests.

Both Gilbert and Nancy Kent, president of the Mississippi chapter of the American Federation of Teachers, said the evaluation system is too untried to be used as the basis of a merit pay system. They also said they’re generally opposed to basing pay on standardized test scores.

“This is not supposed to be an evaluation process to get you,” Kent said. “It’s supposed to be an evaluation process to help the teachers improve.”

Rachel Canter, executive director of Mississippi First, which pushes for changes in the state’s school system, said that evaluations should carry consequences. Canter said she favors merit pay because equal pay for all is “disrespectful” to the best teachers. “It gives the message to people that every teacher is exactly the same,” she said.

Bryant suggested that the Legislature change the law to take money used for annual raises, and instead send it to districts for merit pay plans. He also suggested lawmakers find other money that could be redirected to merit raises and that districts use local supplements.

The governor said the Clarksdale, Gulfport, Lamar County and Rankin County districts have expressed interest in taking part in a trial program.

Districts could also pay more to teachers in subject areas where teachers are in short supply or teach in schools with low test scores or large numbers of students in poverty.

Districts would still be required to pay minimum starting salaries. But co-author Julie Jordan, the head of Mississippi State’s Research & Curriculum unit, said districts should be free to design their own systems to meet local goals and needs. For example, she said one system might want to pay more to increase its high school graduation rate and another system might want to pay more to improve elementary school reading scores.

Teachers or administrators who get “unsatisfactory” grades on their evaluations would be barred from getting pay raises.

Gilbert said the step-raise system was an achievement that eliminated local favoritism as a factor in teacher salaries and said it’s “premature” to dismantle that system.