July 15 (Reuters) - Canada's resource-heavy main stock

index opened slightly lower on Monday, hurt by a firmer dollar

following an assassination attempt at Donald Trump, that

increased his winning bets in the U.S. presidential elections.

At 9:37 a.m. ET (13:37 GMT), the Toronto Stock Exchange's

S&P/TSX composite index was down 20.07 points, or

0.09%, at 22,653.45.