THERE BEING NO APPETITE in Annapolis for an increase in the gasoline tax, Gov. Harry Hughes is trying out a new recipe for financing transportation projects throughout the state: add a dash of dollars to car registration fees, pour some corporate income-tax money into the transportation fund, blend in the auto excise tax take and then warm gradually until swallowed by the legislature. When served in a package and garnished with a budget surplus of general revenues, this should serve two transit systems and a host of rural highway projects. Given the moods and needs that Gov. Hughes is catering to this year, the proposal is both sensible and sound.

Though the governor's preference for a gasoline tax increase was well founded, the necessity of establishing a federally mandated "stable and reliable" source of financing for Metro makes General Assembly approval of some revenue plan essential. In proposing a $5-to-$8 increase in the yearly auto tag fees and the transfer of portions of two existing taxes to the state's transportation fund, Gov. Hughes would find money for Metro, the Baltimore subway and roads.

The plan would increase the state share of Metro's operating deficit in Maryland from the current 40 percent to 75 percent, pay the entire cost of building a 13-mile Baltimore rail system and finance local road programs sought by localities in various parts of the state. This should appeal to rural as well as suburban legislators since it balances requests for roads and rails.

Already there have been a few predictable harrumphs from the lawmakers, who would just as soon not hear about any increases in anything. But if this relatively tiny change in the tag fees is all it takes to settle the most important matter before the General Assembly, thoughtful legislators should seize the opportunity to support it.