* CBOT May corn rose 2-1/4 cents to $3.73 per bushel.
* The contract earlier dropped to a low of $3.66 a bushel, the weakest since Sept. 20.
* The most-active contract posted a weekly decline of almost 0.6 percent.
* Concerns around export competition capped gains on Friday. Brazil's 2018/2019 second corn crop was estimated at 65.8 million tonnes versus 64.9 million tonnes in a prior forecast, INTL FCStone said.
* Investors continue to watch for news on US-China trade talks on hopes that a deal could include a large grain purchase by China.
* US President Donald Trump on Thursday warned he could walk away from a trade deal with China if it were not good enough, even as his economic advisers touted "fantastic" progress towards an agreement to end the dispute.