Chicago wheat prices rose on Monday as traders worried about dry weather shrinking harvests in Argentina and Australia and Russian attacks damaging Ukraine's ability to export grain.
Corn and soybean prices also rose.
"Argentina's 2023 crop is likely being downgraded, as is Australia's. And the starting point for 2024 Black Sea crops is poor," independent analyst Tobin Gorey wrote in a post on LinkedIn.
"None of them on their own are likely to lift global prices much. Woven together, though, they may be enough," Gorey added.
The most-active Chicago Board of Trade (CBOT) wheat futures Wv1 were up 1.3% at $5.75-3/4 a bushel by 0256 GMT, having recovered from last month's three-year low of $5.40.
CBOT corn Cv1 rose 0.6% to $4.95 a bushel and soybeans Sv1 were 0.7% higher at $12.74-3/4 a bushel.
Poor production in southern hemisphere countries that harvest later in the year would tighten a market currently awash with exports of cheap wheat from Russia, which has had two bumper harvests in a row.
Argentina's core agricultural farmland could suffer 'massive losses' in wheat yields due to another drought, the Rosario Grains Exchange said, though it has not yet changed its forecast for the country's production.
In Australia, meanwhile, areas of severe rainfall deficiency expanded during the driest September on record, the country's weather bureau said.
Much-needed rains in some parts of Australia last week helped stabilise crop expectations, but wheat production is forecast to come in around two-fifths lower than last year.
In Ukraine, another major shipper, grain exports are down 27.8% to 6.92 million metric tons so far in the 2023/24 July-June season, the government said, as Russian attacks on the country's export infrastructure continued on Friday and Sunday.
Ukraine has harvested 46.7 million tons of grain and oilseeds from the new 2023 harvest so far, including 22.2 million tons of wheat, the agriculture ministry said on Friday.
Money managers in the week ended 3 October expanded their sizable net short in CBOT wheat futures and options to 98,788 contracts from 96,384 a week earlier.
Speculators also slashed their net long position in CBOT soybeans to 5,001 contracts from 30,058 a week earlier, taking them close to a net short that they last held in April 2020.
Corn and soybean prices are under pressure from the ongoing US harvest, which is adding to supply, and record production in Brazil, the biggest exporter.
However, analysts polled by Reuters expect the US Department of Agriculture in a report due on Oct. 12 to slightly downgrade its estimates for the U.S. corn and soy harvests.
Reuters also polled analysts on US forecasts for 2023-24 US and global ending stocks for wheat, corn and soybeans.
The drought in Argentina is meanwhile delaying the planting of corn and if dry weather persists the area planted could fall, the Rosario exchange and Buenos Aires grains exchange said.