SINGAPORE, Sept 18 (Reuters) - Chicago soybean futures extended gains on Friday with the market set for a sixth weekly gain, underpinned by strong demand from top buyer China.

Corn is poised for a second weekly gain while wheat is in positive territory this week after closing lower last week.

FUNDAMENTALS

* The most-active soybean contract on the Chicago Board of Trade added 0.6% to $10.34-3/4 a bushel, as of 0040 GMT. The market is up near 4% this week and on track for almost 20% rally in six weeks.

* Corn gained 2.3% so far this week and wheat rose 3.6% this week.

* Soybeans led the move higher, fuelled by persistent Chinese demand. The U.S. Department of Agriculture has announced U.S. soy sales to China in each of the past 10 business days, including Thursday's confirmation of 264,000 tonnes, along with an additional 360,500 tonnes sold to unknown destinations.

* China on Thursday set its low tariff rate quota for wheat, corn and rice imports in 2021 at the same volumes as previous years.

* The setting of the volumes came as Chinese buyers have been ramping up large volumes of corn imports from the United States, and increased imports of wheat.

* High soybean prices are expected to support planting in Argentina this season, but that will be balanced by dry weather, which is driving farmers across the Pampas grains belt to favour late-season corn, which also has attractive prices.

MARKET NEWS

* Asian shares looked set to rise on Friday following pledges by central bankers globally to do whatever it takes to support the economic recovery while oil perked up as OPEC threatened to clamp down on member states that did not cut output.

DATA/EVENTS (GMT) 0600 UK Retail Sales MM, YY Aug 0600 UK Retail Sales Ex-Fuel MM Aug 1400 US U Mich Sentiment Prelim Sept (Reporting by Naveen Thukral, Editing by Sherry Jacob-Phillips)