March 17 (Reuters) - Wall Street’s main indexes opened lower on Wednesday as U.S. bond yields spiked ahead of the Federal Reserve’s policy statement which could provide hints on whether the central bank would raise interest rates sooner than expected. The Dow Jones Industrial Average fell 0.4 points at the open to 32825.52. The S&P 500 fell 13.1 points, or 0.33%, at the open to 3949.57, while the Nasdaq Composite dropped 134.7 points, or 1.00%, to 13336.915 at the opening bell. (Reporting by Shashank Nayar in Bengaluru; Editing by Maju Samuel)