Wheat and corn drew additional support from a weaker dollar and concerns about continued grain shipments from Ukraine amid Russian criticism of a U.N.-brokered export corridor deal.
Grain traders also took positions ahead of a monthly U.S. Department of Agriculture (USDA) supply-and-demand report due on Monday, when the agency is expected to lower its U.S. harvest forecasts, particularly for corn.
"Some people are thinking USDA could come in with their (corn) yield below what the trade estimates are," said Ted Seifried, chief agriculture strategist for the Zaner Group.
"We're all in agreement that the yield is going to come down. It's just a question of how much," Seifried added.
Chicago Board of Trade December corn futures CZ2 were up 16-1/2 cents at $6.85 a bushel after holding technical chart support at its 100-day moving average. The contract rose 2.9% on the week, a third straight weekly gain, as worries about shrinking yield prospects lifted the market.
November soybeans SX2 gained 26-1/4 cents to $14.12-1/4 a bushel after sinking to a one-month low in the prior session. But the contract was down for a second straight week, shedding 0.6%.
CBOT December wheat WZ2 jumped 40-1/2 cents to $8.69-1/2 a bushel for a gain of 7.2% in the week, its third consecutive weekly advance.
Grain Export Deal
Uncertainty over a Ukrainian grain export deal underpinned markets as leaders of Russia and Turkey plan to meet next week to discuss the deal both have criticised.
Traders are also monitoring the food inflation implications a partial rice export ban by India. The country banned exports of broken rice and imposed a 20% duty on exports of various grades of rice on Thursday.