Chicago Board of Trade (CBOT) corn, soybean futures closed higher on Friday amid fresh export news from the US government and ongoing worries about unfavorable weather in South America, while wheat ended flat.

The most active corn contract for May delivery added 4.5 cents, or 1.2 percent, to 3.785 U.S. dollars per bushel. Soybean for May delivery rose 8 cents, or 0.84 percent, to 9.56 dollars per bushel. Meanwhile, May wheat delivery was unchanged at 4.5975 dollars per bushel.

Corn prices extended gains to a fourth straight session on Friday as the U.S. Department of Agriculture(USDA) reported that more than 340,000 tons of corn were sold to an unknown destination.

Analysts said speculators holding a large short position in the corn market, kept cutting their net-bearish positions amid worries that dryness in Brazil would curb output of some corn crops.

Soybeans rebounded from losses in the early session after the USDA said that more than 130.000 tons of U.S. soybeans were booked for delivery to China during the 2016/17 crop year.

Meanwhile, a weaker U.S. dollar gave Chicago grains and soybeans an upward jolt.

The U.S. Dollar Index, a measure of the dollar against six major currencies, fell by more than 0.4 percent during the session.

A stronger U.S. dollar is bearish for greenback-priced agricultural commodities, as it will make them more expensive for users holding other currencies.

For the week, the most active corn contract for May delivery rose by 4.5 percent, May wheat lost 0.1 percent, while May soybeans gained 4.3 percent.