CBOT Trends-Wheat down 3-4 cents, corn down 1-2, soy down 1 to 3

CHICAGO, Feb 4 (Reuters) - The following are U.S. expectations for the resumption of grain and soy complex trading at the Chicago Board of Trade at 8:30 a.m. CST (1430 GMT) on Wednesday:

WHEAT - Down 3 to 4 cents per bushel

• CBOT wheat Wv1 fell, curbed by a firm dollar as traders assessed weather risks. GRA/

• The dollar index =USD rose on Wednesday, making U.S. crops more expensive internationally. FRX/

• Volatility in the dollar, which hit a four-year low last week before rebounding following Friday's nomination of Kevin Warsh as the next Federal Reserve chair, has weighed on grain and wider commodity markets.

• While snow cover was expected to limit wheat crop damage in U.S., Ukrainian and Russian plains, a prolonged period of severe cold in the Black Sea region was nonetheless sustaining some market concern, according to traders.

• March soft red winter wheat WH26 was last down 3-1/2 cents at $5.25-1/4 per bushel. K.C. March hard red winter wheat KWH26 was last down 4-3/4 cents at $5.30 per bushel and Minneapolis March spring wheat MWEH26 was last down 3/4 cent at $5.67-1/2 per bushel.

CORN - Down 1 to 2 cents per bushel

• CBOT corn futures Cv1 dipped on strength in the dollar, but gained support from new biofuel tax credit guidance in the U.S.

• The U.S. Treasury Department on Tuesday released updated guidance on biofuel tax credits, a move welcomed by traders as giving clarity to biofuel producers. The news supported corn, which is used to make ethanol fuel.

• CBOT March corn CH26 was last down 1-3/4 cents at $4.26-3/4 per bushel.

SOYBEANS - Down 1 to 3 cents per bushel

• CBOT soybean futures Sv1 fell after a bounce yesterday but new guidance on U.S. biofuel tax credits kept a floor under prices.

• Soyoil held steady after a day-earlier rally supported by the guidance on tax credits for biofuel, a major source of demand for soyoil.

• CBOT March soybeans SH26 were last down 2-3/4 cents at $10.63 per bushel.