Cotton futures dipped on Wednesday, weighed down by a stronger dollar and continued selling by speculators and producers, as traders assessed the potential impact of U.S. President Donald Trump's tariff threats.

* Cotton contracts for March (CTc1) fell 0.29 cent, or 0.4%, at 66.69 cents per lb at 11:55 a.m. ET (16:55 GMT).

* The dollar index, which measures the currency against six others, rose 0.1%. A stronger dollar makes greenback-priced cotton more expensive for overseas buyers.

* "It's the same two negatives that have plagued the market for some time, and those are bearish speculators that continue to sell after every rally and then actual producers who are holding the real crop, and every time it rallies, they're selling their cash cotton," said Keith Brown, principal at cotton broker Keith Brown and Co in Georgia.

* "But cotton doesn't trade in a vacuum and, as you see, higher corn and beans, higher energies, gold, stock market, I think, in time, cotton will level off and start coming up."

* Elsewhere, Chicago grain futures rose on Wednesday as traders waited to see if U.S. President Donald Trump would follow through on threats to impose 25% tariffs on imports from Canada and Mexico this weekend.

* U.S. President Trump still plans to make good on his promise to issue tariffs on Canada and Mexico on Saturday, the White House spokeswoman Karoline Leavitt told reporters on Tuesday.

* Oil prices edged lower on Wednesday on a rise in U.S. crude stockpiles and easing concern over Libyan supply, with U.S. tariffs on Canadian and Mexican imports also in focus.

* Lower oil prices make cotton-substitute polyester less expensive.