U.S. wheat futures fell 1% on Wednesday after a three-day rally, and corn retreated from a five-week high, as investors locked in profits while keeping a close watch on the nearly seven week-long Russia-Ukraine crisis.

While the war has hampered Black Sea exports from Russia and Ukraine, two of the world's major grain suppliers, a potentially record-large wheat harvest in India in 2022/23 offers big buyers an alternative source. The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 1.0% to $11.01-1/4 a bushel by 1220 GMT.

Egypt is considering adding wheat from India to 16 other national import origins accepted by its state grains buyer, as it seeks to shore up purchases disrupted by Russia's invasion of Ukraine.

In Wednesday's tender, it had limited purchases to European origins only. Still, overall global supply is expected to remain tight, with Russian President Vladimir Putin giving his strongest signal yet that the war in Ukraine will grind on as he warned peace talks were at a dead end.

"The tightness of grain supply this year is stronger than the decline in demand," analysts at Zhongzhou Futures in China said in a note. CBOT soybeans lost 0.1% to $16.68 a bushel after official data showed soybeans purchases by top importer China slid in March from the previous year's figure. CBOT corn shed 0.6% to $7.71-1/2 a bushel, after advancing to $7.79 in the previous session, its highest since March 7.

Corn had rallied on Tuesday, buoyed by a plan by U.S. President Joe Biden's administration to raise demand for biofuels including corn-based ethanol, and worries about a slow start to U.S. planting.

Adding to supply worries, Argentine truck owners extended a grains transport strike in the world's leading exporter of processed soy and number two shipper of corn. 

(Reporting by Enrico Dela Cruz in Manila Editing by Sherry Jacob-Phillips and Mark Potter)