CANBERRA, Aug 6 (Reuters) - U.S. corn futures fell on Friday, though the grain was on course to record weekly gains of nearly 1% amid strong U.S. export demand and concerns about global supplies. FUNDAMENTALS * The most-active corn futures on the Chicago Board of Trade was down 0.5% at $5.50-1/4 a bushel after closing up 1.1% on Thursday. * Corn is up 0.9% for the week, the second straight weekly gain. * Soybeans futures are down 1.6% for the week, the third straight weekly loss. * Wheat futures are up 1% for the week, the second straight weekly gain. * U.S. exporters sold 898,400 tonnes of corn during the week ended July 29, topping market expectations. Exporters also sold 436,200 tonnes of soybeans. * Soybeans also supported by a daily sales notification of 300,000 tonnes of soybeans for delivery to unknown destinations during the 2021/2022 marketing year. * Consulting firm Agroconsult pegged the South American producer’s second-crop at 60.9 million tonnes, down 4.4 million tonnes from its previous estimate. MARKET NEWS * U.S. crude oil futures were on track for their biggest weekly decline since late October on Friday, with prices coming under pressure as top consumers impose travel restrictions amid the spread of the Delta variant of the coronavirus.