Pubco Corp's net income was down in 1979, in part because of high interest costs and curtailment of operations by a strike and bad weather, the chairman of the nation's 12th-largest publishing company told an annual meeting yesterday.

"Every time the prime rate goes down one point, it means $100,000 a year in savings to Pubco," said Charles W. Lockyer, chairman of the board and president of the Glenn Dale, Md., firm. Pubco includes Merkle Press Inc. and Byron S. Adams Printing Inc. of Washington, a legal and financial printing firm.

Lockyer said the company recently has arranged $13 million in new financing, which should allow Pubco to be more flexible and to increase sales and earnings.

Pubco's net income in 1979 was $765,000 (24 cents a share) compared with net income of $1.17 million (42 cents) in 1978.

Net earnings were also down in the first quarter of 1980 to $353,867 (9 cents) in the same period in 1979. However, the company's operating income for the first quarter increased by 25 percent over the same period last year, Lockyer said. The gain reflected a $160,188 capital gain from the sale of a fully depreciated printing press, he said.

Pubco, which employes about 800 workers nationally, has its headquarters on 87 acres in Glenn Dale, Md., where it moved in 1975. The corporation, with more than $53 million in sales, grew out of a small book-distributing company founded by Lockyer in 1958. The original business was located above a hardware store on L Street NW.

The company prints and mails approximately 10 million pieces a day in Glenn Dale, including national magazines and union newspapers.

Lockyer fielded a variety of questions from a handful of stockholders who attended yesterday's meeting, including some about the corporation's earnings and the hiring of Lockyer's son as chief financial officer and treasurer.

Lockyer noted that his son previously headed commercial credit operations for Fidelity Bank in Philadeliphia and took a pay cut to go to work for Pubco.