* Wheat down on improving U.S. crop condition, canceled sales
* Soybeans correct lower from recent rally
* Corn climbs on possible farmer switch to soy, technical buys (Adds closing U.S. prices)
By Rod Nickel
WINNIPEG, April 7 (Reuters) - Chicago wheat dropped on Thursday for the fourth straight session on lackluster weekly export sales and the improving condition of the U.S. winter crop.
Soybeans slid in a correction from Monday's highest price since Aug. 17 and corn rose on speculation U.S. farmers may switch some acres to soy.
The most-active May wheat contract on the Chicago Board of Trade dropped six cents or 1.1 percent to $4.57 a bushel, touching a one-week low of $4.56-3/4.
The USDA's export sales report showed net cancellations of old-crop U.S. wheat totaling 58,100 tonnes in the week to March 31, the weakest results in the current marketing year. Analysts had expected old-crop net sales of 150,000 to 350,000 tonnes.
"Wheat is kind of taking it from all sides here," said Terry Linn, broker at The Linn Group. "All things considered, it's doing an OK job of composing itself and not collapsing.
"But certainly not very encouraging to the wheat bull."
The U.S. Department of Agriculture on Tuesday rated 59 percent of U.S. winter wheat as being in good-to-excellent condition, better than expected.
Forecasts for rain this weekend and later in the southern U.S. Plains have also eased dryness concerns, Linn said.
Egypt's state grain buyer, the General Authority for Supply Commodities (GASC), said on Thursday it bought 60,000 tonnes of French wheat in a tender.
May soybeans fell 3-1/2 cents or 0.4 percent to $9.04-1/2 a bushel.
Along with a price correction, soybeans are under pressure from a view that higher prices will encourage U.S. farmers to plant some additional soybean acres instead of corn, Linn said.
May corn added 3-1/2 cents or 1 percent to $3.61-1/2 a bushel, after hitting $3.62, the highest since March 31.
Technical buying and brisk U.S. export sales propped up corn, traders said. USDA reported export sales of U.S. corn in the week to March 31 at 945,200 tonnes for 2015/16 and 175,100 tonnes for 2016/17, in line with trade expectations.
China is also aiming to reduce corn planting by about 8.2 million acres by 2020 and boost soybean output, in order to meet domestic food demand, the ministry of agriculture said on Thursday. (Additional reporting by Julie Ingwersen in Chicago; Editing by James Dalgleish and Tom Brown)