Europe's wheat prices ended a losing streak, and rapeseed hit its highest for nearly a year, after US officials cut estimates for both crops, citing the region's erratic spring weather.

The USDA sliced its estimate for the EU wheat harvest by 2.1 million tonnes to 143 million tonnes.

The rapeseed estimate was cut by 500,000 tonnes to 21 million tonnes, leaving it out of the running for beating last year's 21.45 million-tonne harvest.

Both revisions reflected the dry spring which affected parts of the west of the EU, notably France and the UK, and the storms which dumped "two or three times the average" rainfall on many central European countries.

"Excessive rainfall was particularly unfavourable in Poland, Slovakia, and Hungary," the USDA said.

"The rains affected the wheat crop, which was in the jointing to flowering stages, and the rapeseed crop, which was primarily in the flowering stage."

Paris wheat prices have been on a downward run over the last two weeks, losing some 7%, as rains refreshed parched crops in France, Europe's biggest wheat producer.

The EU revision was the largest of a series of cuts to forecasts for wheat producers, with hopes for Russia's harvest cut thanks to higher-than-expected rates of winterkill, and a "new and virulent" strain of yellow rust denting hopes in Syria and Turkey.

These cuts were partly offset by raised hopes for Ukraine's crop, following rains, and of higher winter wheat yields in the US, leaving the overall reduction to world output at 3.7 million tonnes.

However, the USDA flagged concerns over the quality of the US crop saying that lower than expected protein levels in the hard red winter wheat, for which harvesting is in its early stages, had reduced prices prospects for many producers.