SINGAPORE, June 20 (Reuters) - Chicago wheat futures extended their decline to a fourth straight session on Thursday as higher crop production forecasts in major exporting countries eased supply fears, with the September contract slipping to its lowest in two months.

Corn and soybean futures edged lower as worries over a heat wave set to strike U.S. corn and soy crops subsided.

FUNDAMENTALS

* With the Chicago Board of Trade (CBOT) reopening after a public holiday on Wednesday, the most-active wheat contract was down 0.1% at $5.98-1/2 a bushel at 0001 GMT, having fallen as low as $5.97.

* CBOT soybeans dipped 0.2% to $11.71-1/2 a bushel and corn was trading 0.5% lower at $4.47-3/4 a bushel.

* Russia's IKAR agricultural consultancy raised its forecasts for the country's wheat crop to 82 million metric tons from 81.5 million tons, it said on Wednesday. Russia is the world's biggest wheat exporter.

* In Argentina, the Buenos Aires Grains Exchange bumped up its forecast for wheat planting, saying higher wheat prices and lower input costs were pushing more farmers to sow the crop despite dryness in some areas.

* Germany's 2024 wheat crop will fall 5.5% on the year to 20.34 million metric tons but recent rain should have no major impact, the country's association of farm cooperatives said in its latest harvest estimate.

* Moving to corn, Ukraine's production was revised upwards by 0.8% amid improved soil moisture levels across key cropping regions, LSEG Commodities Research said in a report.

* A heat wave in the U.S. Midwest this week is raising concerns about the eastern Corn Belt's corn and soy crops, but agronomists said it should have limited impact on plants because they are still in the vegetative growth stage.

* Commodity funds were net buyers of CBOT corn, soybean, soymeal and soyoil futures contracts on Tuesday and net sellers of wheat, traders said.

MARKETS NEWS

* Global stocks hit record highs on Wednesday, driven by a rally in tech shares that has made AI chipmaker Nvidia the world's most valuable company, while the dollar stalled as soft U.S. retail sales data suggested interest rates could fall this year.

(Reporting by Cassandra Yap; Editing by Eileen Soreng)