Several of the country's major retailers yesterday reported disappointing earnings for the third quarter, when soft sales forced them to mark down merchandise.

J. C. Penney & Co, the third-largest retailer, posted a 6.6 percent gain in net income for the three-month period ended Oct. 27 over a year earlier. Allied Stores Corp., which owns Garfinckel's, saw a drop of 8 percent. No. 9 May Department Stores Co., parent of the Hecht Co., enjoyed a 12 percent gain.

"On balance, the earnings were on the disappointing side," said Jeffrey Edelman, a retail analyst with the investment firm Dean Witter Reynolds Inc. "For the most part, they have been reflecting heavy markdowns. Sales have been soft, inventories have been high."

Penney, based in New York, said its third-quarter net income totaled $101 million ($1.34 a share), compared with $94 million ($1.26) a year earlier. Sales rose 10.8 percent to $2.9 billion from $2.7 billion.

For the first nine months of the year, Penney posted a 5 percent profit increase to $219 million ($2.92) from $207 million ($2.78) last year.

Nine-month sales rose 15 percent to $8.2 billion from $7.1 billion.

May, of St. Louis, said its third-quarter net income came to $39.6 million (92 cents a share) vs. $35.4 million (82 cents) a year ago. Sales jumped 13 percent to $1.13 billion from $1 billion. So far this year, net income rose 20 percent to $104.1 million ($2.41) from $86.6 million ($2.00). Nine-month sales climbed 14 percent to $3.12 billion from $2.75 billion.

Allied, of New York, said its third-quarter net income was $17.6 million (84 cents a share) vs. $19.2 million (92 cents) a year ago.

Sales increased 5.5 percent to $932 million from $883 million. For the year-to-date, net income rose 1.5 percent from $48 million ($2.32) to $49 million ($2.34). Nine-month sales gained 8 percent to $2.65 billion from $2.44 billion.