The Department of Transportation, in a concession to legislators from farm states, has proposed granting states the option of issuing restricted commercial drivers licenses to seasonal drivers working in the farming industries.

If approved, the measure means about 45,000 drivers will not have to take the knowledge and skills portion of the CDL test, said Tom Jasien, a spokesman for DOT's Federal Highway Administration.This works out to about 1 percent of the nation's 4.5 million commercial drivers who are required to have a CDL by April 1.

Under the DOT proposal, only seasonal employees would be eligible for the restricted license, which would be valid only while drivers are performing farm-related services.

"It's a fine idea," said Ronald T. Wagner Jr., director of revenue, Missouri State Department of Transportation. "Missouri is an agricultural community. This farm exemption will benefit us in the respect that the CDL law was intended to make our roads safe. The farmers, as a general rule, are not on the highways to the extent of the interstate truckers."

The proposal would chiefly benefit drivers hauling for agri-chemical shippers, custom harvesters, livestock feeders and farm retail outlets and suppliers.

The American Trucking Associations has opposed the granting of exemptions to the farming industry.

''Granting any more waivers opens the door for others to follow and makes the program ineffective," said Thomas J. Donohue, the ATA's president and chief executive officer, in testimony before the Surface Transportation Subcommittee of the House Public Works and Transportation Committee.

Rep. Norman Y. Mineta, D-Calif., chairman of the Surface Transportation Subcommittee, also has opposed granting additional waivers to the CDL regulations.

Comments on the proposal are due within 10 days of its publication in the Federal Register.