Chicago wheat futures were on track for their biggest weekly gain since late June 2015 on Friday as forecasts of more dry weather across the US Plains supported the market.
Soybeans are poised for a fourth consecutive week of gains as a severe drought in Argentina threatens to reduce global surplus, while corn is on track for its biggest rally since early July, reports Reuters.
Wheat futures have rallied for the last six sessions with dry weather expected to curb US winter crop yields.
Agricultural meteorologists are forecasting below-normal moisture levels over the next few weeks which are expected further damage the crop.
The Chicago Board of Trade most-active wheat contract has jumped 11.3 per cent this week, the market's biggest rally since June 2015. Soybeans are up 2.8 per cent this week while corn has gained 5.7 per cent.
Dry weather in Argentina, the world's biggest soyoil and soymeal supplier, is supporting prices.
"We are seeing pretty strong move in wheat prices and it is all because of U.S. winter wheat crop," said Phin Ziebell, an agribusiness economist for National Australia Bank.
"It is very interesting to see this, we are adjusting our grain-price outlook as there is potential for more upside. There is likely to be supply response to this price rally."
Crop conditions for drought-battered corn and soybeans in Argentina fell further this week, and ratings among the top three provinces are now on average about 23 percentage points lower than a month ago.
The poor conditions prompted the Buenos Aires Grain Exchange to slash the country's soybean crop on Thursday to 44 million tonnes from its previous estimate of 47 million. It maintained corn at 37 million tonnes.
About 57.5 million tonnes of soybeans were harvested a year ago, along with roughly 40 million tonnes of corn.
Argentina's lower production is expected generate more demand for U.S. soybeans and corn.
The US Agriculture Department on Thursday morning reported weekly soybean export sales of 979,900 tonnes, which topped forecasts for 400,000 tonnes to 800,000 tonnes.
The agency also announced snap soybean sales on Thursday that totalled 246,000 tonnes, including 120,000 tonnes for delivery to China during the current marketing year.
