CHICAGO, June 11 (Reuters) - U.S. wheat futures bounced on Tuesday after a nine-session slide, with the benchmark Chicago Board of Trade (CBOT) July wheat contract lifted by bargain buying and renewed worries about crops in top global exporter Russia, brokers said.

CBOT soybean and corn futures ended lower on relatively strong U.S. condition ratings and position-squaring a day ahead of monthly crop supply/demand reports due from the U.S. Department of Agriculture.

CBOT July wheat settled up 19 cents, or 3.1%, at $6.26-1/2 per bushel, rallying after a dip to $6.05-1/2, the contract's lowest since May 3. Technical traders noted chart support at the contract's 100-day moving average near $6.04.

CBOT July soybeans ended down 10-1/4 cents at $11.78 a bushel and July corn finished down 2-1/4 cents at $4.49-1/2 a bushel.

Wheat jumped after the head of Russia's grain union said frosts in Russia have affected between 15% and 30% of winter grains, varying by region, a much higher figure than suggested by the agriculture ministry.

Benchmark CBOT wheat had fallen more than $1 a bushel since May 28, pressured by the start of the Northern Hemisphere harvest and a temporary ban on imports by major buyer Turkey.

Some saw the market as over-sold and due for a bounce, especially given the news about Russian frost damage and a surprise drop in weekly U.S. winter and spring wheat condition ratings.

"The recent sharp fall in wheat prices was partly attributed to the rapid progress of the harvest in the USA," Commerzbank said in a note. "However, it is still too early to draw conclusions about the ongoing harvest."

Fresh export business lent support. Top buyer Egypt booked 400,000 metric tons of Black Sea-origin wheat in an international tender.

CBOT soybean futures declined but held above a one-month low set earlier this week, and corn futures sagged as brokers awaited monthly USDA reports due on Wednesday. Analysts surveyed by Reuters on average expect the USDA to raise its forecasts of U.S. 2023/24 and 2024/25 soybean ending stocks, and lower its forecasts for corn inventories.

Meanwhile, the U.S. corn and soybean crops are off to a strong start. The USDA late Monday rated 74% of the U.S. corn crop in "good-to-excellent" condition, down a point from last week but still the highest for this time of year since 2020.

Soybeans were rated 72% "good-to-excellent" in the USDA's first ratings of 2024 for the oilseed, in line with trade expectations. (Reporting by Julie Ingwersen; additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Tomasz Janowski and Stephen Coates)