A giant Japanese trading company has purchased the family-owned Stegner Grain & Seed Co., a diversified barge-loading and grain storage company in Lewiston, Idaho.

Columbia Grain Inc., a Portland-based subsidiary of Marubeni Corp. of Tokyo, said Monday it agreed to buy Stegner for an undisclosed price.

The sale is expected to close by April, about the time that a proposed salmon-saving drawdown of the Snake River would be initiated.

Officials from both companies did not return telephone calls, but observers speculated that Columbia Grain may be attempting to increase its sources of high-quality grain Pacific Rim flour mills are demanding.

“If they (Japanese) can’t buy what they want, they’ll originate what they want from their own elevators,” said Mike Dunlap, Spokane regional manager of Intermountain Canola-Cargill Foods.

Foreign millers for years have complained about Northwest exporters delivering poor quality grain that was not suitable for producing the best cakes, noodles and other products.

A statement from Stegner said a new division of Columbia Grain will be created to merge certain operations from both companies. The Lewiston-based division will retain the Stegner name and provide licensed grain storage capacity of about 11.7 million bushels.

Columbia Grain operations included in the division would be its barge-loading facility at Central Ferry, Wash., and a sales office in Colfax.

Stegner assets would include its Port of Wilma barge-loading elevator near Clarkston, Wash.; a Pullman seed processing plant; a sales office in Great Falls, Mont., elevators in four North Idaho communities; and six dry pea and lentil processing plants.

The sale also includes the Nezperce Storage Co. and its feed operations, which Stegner bought late last month. It does not include the historic downtown Lewiston Means Building owned by the June Stegner family.

Columbia Grain is a giant exporter that operates a Portland terminal for loading ocean vessels, as well as at least seven unit train facilities in Montana. Its parent, Marubeni, employs 9,600 people and reported 1993 sales of $145 million.

The Stegners would be retained by Columbia Grain to forge the new division, the statement said. But it did not say whether certain duplicating operations would remain open.

Billy Wood, chairman of Lewis-Clark Terminal Association, a cooperative that competes against Stegner, said he didn’t think Columbia Grain’s purchase would have much affect on the local grain trading business.