A Virginia General Assembly subcommittee called today for eliminating jail terms for those convicted the first time of possessing marijuana for personal use. The panel legislators also urged reductions in penalties for other marijuana convictions.

The subcommittee criticized past police emphasis on arrests for possession of small amounts of marijuana and said a major purpose of its recommendations is to encourage more vigorous prosecution for distributing large quantities of marijuana and for crimes involving more harmful drugs.

The maximum penalty for a first conviction of marijuana possession for personal use would be reduced from a year in jail and a $1,000 fine to a $500 fine. The current maximum penalty would still apply to subsequent convictions.

Ten states have removed the possibility of jail sentences for first offenders convicted of marijuana possession for personal use.

Sen. Frederick C. Boucher (D-Abingdon), chairman of the subcommittee, said he will introduce a bill on Monday that proposes the penalty reductions. Although the bill will raise a controversial issue in an assembly election year, many legislators give it a chance of passage because it has the backing of some influential and conservative members.

The panel's 12 members are all members of the Senate and House of Delegates Courts of Justice Committees and include House Majority Leader A. L. Philpott (D-Henry), who exercises strong influence over criminal justice legislation. Seven of the 20 House Courts of Justice Committee members signed the subcommittee report.

Nevertheless, Del. Richard C. Cranwell (D-Roanoke County), a Courts Committee member who opposes the recommendations, vowed to fight the proposals in the House.

"Maybe I misjudge the mood of the country, but I don't think it's a permissive mood," he said. "I think these proposals will come back to haunt them. They have seven votes in committee, but they need four more."

One of the subcommittee members, Sen. Dudley J. Emick Jr. (D-Botetourt) concurred with all of the recommendations except removing the possible jail term for marijuana possession first offenders.

Attention was focused on that recommendation because it deals with the most common marijuana offense. However, the most drastic sentence reduction proposed deals with cultivation of marijuana for personal use, a crime now punishable by five to 40 years in prison and a fine of up to $25,000, the same penalty provided for distribution of marijuana and other drugs.

The subcommittee recommended that cultivation of marijuana for personal use be treated as a possession offense, thus reducing the penalty to a $500 fine.