GRAINS-Wheat holds firm on US weather risks, soybeans subdued

BEIJING/PARIS, Jan 8 (Reuters) - Chicago wheat futures edged up on Thursday to hold at a one-week high, supported by dry weather affecting U.S. crops and sustained Russian attacks on infrastructure in Ukraine, analysts said.

Soybeans inched down as traders assessed Chinese purchases of U.S. supplies and the prospect of a record harvest in Brazil. Corn also ticked down.

Traders were monitoring investor flows linked to annual changes in the composition of commodity indexes and looking ahead to widely tracked supply and demand data from the U.S. Department of Agriculture next Monday.

Ample global supplies and generally favourable crop weather in South America continued to curb prices.

US WEATHER, RUSSIAN ATTACKS IN UKRAINE FEED WHEAT CONCERNS

The most-active wheat contract Wv1 on the Chicago Board of Trade was up 0.4% at $5.20 a bushel by 1305 GMT. It earlier edged just above a previous one-week high from Wednesday.

Crop conditions data for U.S. wheat has reinforced concern this week over dryness in part of the U.S. Plains.

Ratings for winter wheat declined during December in Kansas, the top U.S. winter wheat producer, and in several other Plains states, USDA data showed on Tuesday.

The strength in wheat "was likely tied to the recent decline in U.S. winter wheat conditions," CM Navigator analyst Donatas Jankauskas said, adding that traders were also positioning before Monday's USDA data that will include a winter wheat acreage estimate.

Intense Russian strikes on Ukraine have, meanwhile, revived worries about disruption to the Black Sea grain trade, taking attention away from U.S.-led efforts to end the conflict.

Russian strikes late on Wednesday knocked out power supplies in almost all of two southeastern Ukrainian regions, the energy ministry said. That followed strikes on two Ukrainian ports earlier on Wednesday.

EYES ON CHINESE US SOY BUYS, EXPECTED BUMPER BRAZIL CROP

CBOT soybeans Sv1 were down 0.1% at $10.65-1/2 a bushel while CBOT corn Cv1 also ticked down 0.1%, to $4.46-1/4 a bushel.

There was market chatter of further purchases of U.S. soybeans by Chinese buyers, after traders reported that state grain stockpiler Sinograin had booked 10 cargoes of U.S. soy at the start of the week.

The head of Brazilian grain traders lobby Anec said that sales of U.S. soybeans to China will partly dent demand from China for Brazilian supply.

However, expectations of a record soybean crop in Brazil, where the harvest is getting under way, capped Chicago prices.

"Soybean prices are still being tempered by expectations of a large crop in South America," said Claire Adams, an agricultural analyst at Bendigo Bank Agribusiness.

In Argentina, another major grain exporter, the Rosario Grains Exchange (BCR) forecasts a record 2025/26 corn harvest of 61 million tons and a soybean harvest of 47 million tons.