Maryland National Corp. yesterday reported net income of $21.2 million ($1.16 a share) for the first quarter of 1986 that ended March 31, which is 33 percent more than its net income of $16 million (99 cents) for the same period last year.

At the same time, United Virginia Bankshares Inc. and First Virginia Banks Inc. reported higher quarterly earnings.

Total assets grew to $8.1 billion, up 19 percent over the first quarter of 1985. In the first quarter, deposits were up 23 percent. Continued growth in the retail-lending portfolio combined with a high rate of growth in noninterest income of 36 percent were the primary factors contributing to current earnings, according to the Baltimore holding company for Maryland National Bank.

*United Virginia Bankshares Inc. reported net income of $20 million ($1.42) for the first quarter that ended March 31, a 29 percent increase over the $15.4 million ($1.23) earned in the first quarter of 1985.

The increase includes the earnings of NS&T Bankshares Inc. of the District, which was acquired last year.

The bank-holding company, based in Richmond, said the growth was a result of strong loan growth and higher noninterest operating income. Average loans were $5.8 billion in the first quarter, which is an increase of 32 percent. Noninterest operating income amounted to $33.7 million, up 35 percent over the same period last year.

*First Virginia Banks Inc. reported net income of $11.5 million (71 cents) for the first quarter that ended March 31, up 24 percent from $9.3 million (57 cents) for the same period last year.

Higher earnings resulted from a 14 percent increase in net interest income. A 19 percent growth in noninterest income also contributed to the earnings growth, the Falls Church company said. Total loans were nearly $2 billion for the first quarter, up 9 percent from $1.8 billion for the same period last year. Deposits increased to nearly $3 billion, up 15 percent.