TREASURIES-Prices gain ahead of Fed, Scottish vote

* U.S. debt rises for second session

* Modest safe-haven bid seen as some investors worry

* Price gains strongest in longer maturities

By Michael Connor

NEW YORK, Sept 16 (Reuters) - U.S. Treasury debt prices rose on Tuesday as buyers fretted over possible shifts in America's ultra loose monetary policy and about the independence referendum in Scotland on Thursday, which could shake global markets.

As stock markets hit a one-month low before a U.S. Federal Reserve policymakers' meeting scheduled to begin Tuesday, prices of Treasuries moved up for a second straight session after a sustained selloff that ended on Friday.

"It's more of a tilt toward quality, as opposed to a flight to quality," said Wilmer Stith, fixed income portfolio manager at Wilmington Trust in Baltimore, Maryland.

The benchmark 10-year Treasury note yield, which stood at 2.613 percent on Friday versus 2.476 percent on Sept. 5, last yielded 2.576 percent on Tuesday. Price was up 3/32.

The 30-year bond was up 3/32 in price to yield 3.33 percent, while shorter maturities were also ahead or flat in early New York trading.

The Fed's two-day policymaking Federal Open Market Committee meeting will be watched for clues on the timing of the first rate hike in more than eight years.

"The market is just waiting with bated breath to see what comes out of the FOMC meeting tomorrow and followed, to a lesser degree, by the Scottish referendum," Stith said.

The Fed on Wednesday will also release economic and interest rate projections, extending its forecast horizon through 2017.

It has said it does not expect to raise rates until 2015, but recent strong data has led Fed officials to acknowledge they may need to act sooner than they thought just a few months ago.

On Thursday, Scottish voters will vote on ending their country's 307-year union with England, possibly breaking up the United Kingdom. The polls show the result is too close to call.

"It's a Pandora (Other OTC: PNDZF - news) 's Box. What does it mean for the UK and the EU? What does it mean for other regions, like Catalonia in Spain?" Stith asked. "It opens more uncertainties, and the last thing Europe needs is more uncertainty." (Reporting By Michael Connor in New York; Editing by Peter Galloway)