Updates with U.S. trading; updates headline, byline, dateline, analyst quotes

By Renee Hickman

CHICAGO, July 23 (Reuters) - Chicago wheat fell back after it climbed to a two-year high on Thursday after attacks on grain vessels and port infrastructure in the Black Sea region prompted ship owners to suspend port arrivals.

Soybeans and corn firmed, tracking higher crude prices.

The most-active wheat contract on the Chicago Board of Trade (CBOT) Wv1 was down 5-3/4 cents to $7.00 a bushel by 11:36 AM CDT, having previously hit its highest point since May 2024.

Soybeans Sv1 rose 5-1/4 cents to $12.44-1/4 a bushel and corn Cv1 gained 2-1/4 cents to $4.87 a bushel.

The wheat rally took a pause, said Randy Place, analyst at the Hightower Report, on profit-taking after being driven by an uptick in hostilities in the Black Sea.

Ukraine's agriculture minister said ship owners had temporarily suspended vessel arrivals at Ukraine's Black Sea ports for agricultural exports after a recent surge in Russian attacks on ports and merchant shipping.

Three traders said ship owners had taken similar decisions at Russia's Black Sea ports. Reuters could not immediately confirm the information.

However, market participants in Russia said operations in Novorossiysk as well as in the ports of Taman and Tuapse were up and running by the morning after the overnight suspension of vessels' entry and exit.

Ukraine's President Volodymyr Zelenskiy said on Thursday that Russia will step up attacks on vessels in the Black Sea, accusing Moscow of plans to undermine Ukraine's grain corridor.

Expectations of lower output are also supporting wheat prices after crop scouts on the first day of an annual three-day tour of North Dakota's hard red spring wheat crop projected an average yield in the southern portion of the state at 46.0 bushels per acre (bpa) on Tuesday evening.

That figure was 8% below the estimate for the same area last year and just above the five-year average of 45.8 bpa.

Meanwhile, the rally in crude oil prices LCOc1, CLc1 lifted soybeans, because of the use of soyoil in biodiesel production, which competes for market share with petroleum.

Greater demand from China also added support, according to Place.

Crude oil prices likewise undergirded corn futures, as did concerns about extreme heat forecast for the western U.S. corn belt.

"There's just nothing really for the bears to grab onto right now," said Place.