International Telephone and Telegraph Corp. reported a 98 cent per share loss for the third quarter, because of a $320 million reserve set aside to cover ITT's investment in a Canadian paper mill that's been closed by a strike.

ITT said it's third-quarter loss of $137 million compared with earnings of $133.5 million a year ago. The quarter's profits were increased by $52.6 million by recent changes in British tax laws and related U.S. accounting changes, the company noted.

For the first nine months of the year, ITT earned $229.5 million ($1.60) compared with $480.7 million ($3.39) a year ago.

Sales and revenues of ITT for the third quarter rose to $5.2 billion from $4.6 billion and new orders for the period increased by 21 percent the company said. Nine-month revenues totalled $15.4 billion, up from $13.7 billion last year.

Rockwell International Corp. said yesterday net income for its 1979 fiscal year increased 48 percent over the same period in 1978.

The diversified aerospace and manufacturing concern said net income was $261.1 million ($7.33 a share), compared with 1978 income of $176.6 million ($5.02 a share).

Sales from continuing operations were $6.2 billion, an increase of 16 percent over 1978 sales of $5.3 billion.

"Considering the momentum built up over the last few years, and strength derived from our balanced diversification, believe the company can anticipate earnings in 1980 higher than 1979's, barring an unduly severe decline in the economy," said Rockwell Chairman Robert Anderson.

Rockwell's automotive, electronics and aerospace businesses each reported improved 1979 earnings. The general industries business, however, reported significantly lower earnings due primarily to losses in the power tool division.

Higher interest income and a lower effective income tax rate also continued to the 1979 earnings results, the company said.

In the fourth quarter, net income totaled $62.1 million ($1.73 a share), compared with a net income of $40.5 million ($1.14 a share) in 1978.

Sales from continuing operations in the quarters were $1.6 billion versus $1.4 billion a year ago.

Rockwell's fourth quarter net from continuing operations was $59.2 million ($1.64 per share), compared with $66 million ($1.88 per share) in the year-earlier quarter.

Genesco Inc. reported yesterday a 25 percent increase in its net income for the first quarter of its fiscal year.

The company said it had first quarter earnings of $3.3 million (19 cents a share), compared with $2.6 million (14 cents a share) last year.

The Nashville-based apparel conglomerate attributed the increase in earnings to a decline in its interest expenses and the absence of a special tax obligation which it had last year on its Canadian operations. Short-term debt has been reduced because the company has sold some of its operations since last year, officials said.

The company said all three of its sectors -- footwear, men's apparel and retailing -- contributed to earnings during the quarter, which ended Oct. 31.

Sales were down from $283.2 million for the first quarter last year to $227.5 million this year, the company said. But it said this was because the 1978 sales figure included the sales of certain operations which have since been divested.