* Wheat prices falls as Ukraine exports soar
* Corn falls on USDA forecast expectations
* Soybean prices drop despite quality downgrade
By Colin Packham
SYDNEY, Aug 12 (Reuters) – U.S. wheat futures fell for the fourth straight session on Tuesday, recording their longest losing rally in a month as concerns over export disruptions from the Black Sea region eased.
Corn fell on expectations that the U.S. Department of Agriculture would confirm bumper domestic production, while soybeans also edged lower despite a surprise deterioration in crop quality last week.
Chicago Board of Trade September wheat futures had dropped 0.64 percent to $5.43 a bushel by 0243 GMT, having closed down 0.5 percent the day before.
“We are seeing some continuation of the sell-off over the last few days as the market becomes less concerned over the Black Sea region,” said Brett Cooper, senior manager of markets at FCStone Australia.
Wheat has fallen for four straight sessions for the first time since July 11, racking up losses during the period of more than 4 percent, giving back more than half of the gains made before the price ease.
Instead of tensions between Russia and Ukraine curbing Black Sea wheat exports, the situation is pushing Ukrainian exports to a multi-year high as toughened borrowing conditions for farmers prompt them to accelerate sales.
December corn futures fell 0.48 percent to $3.66-1/2 a bushel, having closed up 1.3 percent in the previous session.
Analysts said the latest forecast from the USDA, due later in the day, was weighing on prices.
Nearly all the analysts surveyed projected a harvest above 14 billion bushels. The average estimate was 14.253 billion.
Meanwhile, the USDA said good-to-excellent ratings for corn came in at 73 percent, a 10-year high for mid-August. The ratings were steady with a week earlier and matched market forecasts.
November soybean futures fell 0.3 percent to $10.70 a bushel, having closed up 0.7 percent on Monday.
Analysts said soybeans were under pressure from position squaring ahead of the USDA report, though a surprising fall in the condition of the crop was capping losses.
The USDA said good-to-excellent ratings for soybeans were 70 percent as of Aug. 10, down 1 percentage point from a week earlier. Analysts had been expecting soybean conditions to remain steady.
U.S. soybean production and yield forecasts are both expected to be revised upwards by the USDA, according to the average trade estimate in a Reuters survey.
Grains prices at 0243 GMT Contract
Change Pct chg Two-day chg MA 30 RSI CBOT wheat
544.20 47 CBOT corn
381.42 38 CBOT soy
1090.65 71 CBOT rice
$12.73 -$0.01 -0.08%
$13.26 28 WTI crude
$97.80 -$0.28 -0.29%
$101.13 34 Currencies
$1.337 -$0.002 -0.12%
-0.17% Most active contracts Wheat, corn and soy US cents/bushel. Rice: USD per hundredweight RSI 14, exponential (Reporting by Colin Packham)