US STOCKS-S&P 500 up for 6th straight session, Apple falls

* Syria accepts Russia's diplomatic solution to Syria crisis

* Apple (NasdaqGS: AAPL - news) shares fall after unveiling new products

* Goldman Sachs (NYSE: GS-PB - news) , Visa (NYSE: V - news) , Nike (NYSE: NKE - news) to be added to Dow

* McDonald's reports August sales, shares rise

* Indexes up: Dow 0.7 pct, S&P 0.6 pct, Nasdaq 0.5 pct

By Ryan Vlastelica

NEW YORK, Sept 10 (Reuters) - U.S. stocks rose on Tuesday, with the S&P 500 on track for a sixth straight session of gains, as an alternative solution emerged to the Syrian crisis that could avert a possible Western military strike.

Shares of Apple, the most valuable technology company, limited gains, however, and were the biggest drag on the S&P 500 and Nasdaq composite indexes after the company introduced two new iPhones.

Encouraging economic data from China gave investors further reason to buy, with nine of the 10 S&P sectors higher. Energy was the only exception, falling alongside crude oil.

Fears of about a possible military strike against Syria eased after U.S. President Barack Obama said Monday he saw a possible breakthrough after Russia proposed that Syria hand over its chemical weapons for destruction, a proposal Syria supported.

"We don't know if this is just talk or if it could happen, but right now tensions have cooled and the market likes that," said Michael Matousek, head trader at U.S. Global Investors Inc in San Antonio."

Shares of Apple Inc were down 1.7 percent to $497.30 after declining as much as 3 percent. The company unveiled two new versions of its iPhone line, including a cheaper model that could bring the product wider adoption in poorer emerging markets.

The world's most valuable technology company is trying to beat back rivals like Samsung Electronics Co Ltd and Huawei Technologies Co Ltd in markets like India and China, where it has been losing ground.

Geopolitical uncertainty has driven market movement in recent weeks, with investors especially watching global oil prices for any sign that military action could constrain supply.

But oil prices slid more than $2 a barrel as Syria accepted the Russian proposal to give up its chemical weapons, making investors less nervous about the potential for U.S. military strikes against Damascus.

The Dow Jones industrial average was up 108.45 points, or 0.72 percent, at 15,171.57. The Standard & Poor's 500 Index was up 10.41 points, or 0.62 percent, at 1,682.12. The Nasdaq Composite Index was up 17.27 points, or 0.47 percent, at 3,723.46.

After its worst monthly performance since May 2012 in August, the S&P has rallied 3.1 percent over the past six sessions, its longest winning streak since early July.

Economic data in China showed stronger-than-expected industrial output while retail sales grew at the fastest pace this year, reinforcing signs that the world's second-largest economy was stabilizing after slowing for more than two years. On Monday, Wall Street had climbed following strong Chinese export data.

S&P Dow Jones Indices announced the biggest shake-up for the Dow Jones Industrial Average in almost a decade, with Goldman Sachs Group Inc, Visa Inc and Nike Inc replacing Bank of American Corp,Hewlett-Packard Co and Alcoa Inc (NYSE: AA - news) , respectively. The changes will take effect on Sept. 23.

Goldman rose 3.6 percent to $165.26 while Visa gained 2.9 percent to $183.67 and Nike advanced 1.7 percent to $66.51. Alcoa lost 0.4 percent to $8.05, Bank of America (Other OTC: BACYL - news) added 1.2 percent to $14.66 and Hewlett-Packard shed 0.6 percent to $22.22.

"We're not making any moves on the changes, but some market players will try and trade off the ones being added, attempting to get ahead of fund rebalancing," said Matousek, who helps oversee about $1.3 billion. "Over the long term, this shouldn't skew those names one way or the other."

McDonald's Corp gained 0.4 percent to $96.83 after the fast-food restaurant chain reported a better-than-expected 1.9 percent increase in global sales at established restaurants in August.

Urban Outfitters Inc (NasdaqGS: URBN - news) slumped 10 percent to $38.37 as the S&P's biggest loser after Janney Montgomery Scott cut its price target on the stock to $46 from $52.