CANBERRA/PARIS - Chicago corn and soybean futures extended previous session losses on Tuesday, pressured by forecasts for crop-friendly rain in U.S. grain belts this week. Wheat also weakened on expectations of plentiful global supplies. The most active corn contract on the Chicago Board of Trade (CBOT) was down 1% at $4.18 a bushel by 1107 GMT, while soybeans fell 0.3% to $10.22-1/2 a bushel. Traders had been concerned that high temperatures in the U.S. Midwest would damage yields, but after a brief burst of heat mid-week, showers are expected to limit stress to crops, said Commodity Weather Group. The USDA on Monday rated 74% of the U.S. corn crop and 68% of U.S. soybeans in good-to-excellent condition, the highest assessment for corn at this time of year since 2016.

The corn rating was unchanged from the previous week, but soybeans were down from 70% and below the average analyst estimate. Both markets are well supplied, and agribusiness consultancy AgRural on Monday increased its estimate for Brazil's total 2024/25 corn production to 136.3 million tons from 130.6 million tons.

Wheat was down 0.3% at $5.40-3/4 a bushel. The first new-crop wheat from Russia, the world's biggest wheat exporter, has arrived on the market, traders and analysts said on Monday, as top producing regions reported early harvesting results.

Agriculture Minister Oksana Lut told a government meeting on Tuesday the government had trimmed its forecasts for the 2025 wheat harvest, but the harvest was still expected to be large, at 88-90 million metric tons. In Europe, crop monitoring service MARS on Monday raised its forecasts for average winter grain yields in the European Union to above-average levels, but expressed concern for summer crops due to hot weather. Prices at 1107 GMT Last Change Pct Move CBOT wheat 540.75 -1.50 -0.28 CBOT corn 418.00 -4.25 -1.01 CBOT soy 1022.50 -3.50 -0.34 Paris wheat 200.50 -1.50 -0.74 Paris maize 55.57 -0.50 -0.89 Paris rapeseed 470.50 0.00 0.00 Euro/dlr 1.17 0.00 0.06 Most active contracts - Wheat, corn and soy US cents/bushel, Paris futures in euros per tonne