Massachusetts’ economic growth slowed significantly over the summer while the national economy showed a modest pickup, according to two reports released Friday.

Clayton-Matthews, who compiled the data for the ­UMass report, said he expects economic growth in the state to pick up modestly over the next two quarters to an annual rate of 2.3 percent, which is not enough to generate significant job gains. He said he expected “virtually no net employment growth in Massachusetts over the next six months.”