Nov 20 (Reuters) - Canada's main stock index opened lower on Wednesday, as sentiment soured on concerns over political strain between the United States and China, but gains in shares of cannabis producer Canopy Growth Corp limited losses.
* At 9:30 a.m. ET (1430 GMT), the Toronto Stock Exchange's S&P/TSX Composite index was down 30.74 points, or 0.18%, at 16,980.66.
* Canopy Growth shares jumped 10% after Bank of America Merrill Lynch upgraded the stock to "buy." (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Rashmi Aich)