First-quarter profits jumped 35 percent at Sears, Roebuck and Co., the nation's largest retailer.

Most of the higher income resulted from a smaller loss in domestic merchandising operations compared with the 1981 period, Sears said in a statement.

Sears earned $71.4 million (20 cents a share) compared with $52.8 million (17 cents). Revenues climbed 10 percent to $6.44 billion from $5.84 billion.

Sears' Coldwell Banker real estate operations reported first-quarter income of $316,000 on revenues of $129 million compared with income of $26.4 million on revenues of $39.8 million in 1981, while the Dean Witter investment group reported a $10.2 million loss for the quarter compared with a loss of $3.5 million in the 1981 quarter.

Consumer reluctance to invest and lower commissions from depressed stock prices were among the reasons cited by E.F. Hutton Group and Paine Webber Inc. for the poor results.

Hutton, the nation's third-largest brokerage house, said first-quarter profit fell 86 percent to $3.1 million (20 cents a share) from $22.6 million ($1.24). Revenue declined to $315.9 millon from $320.3 million.

Paine Webber, reporting on its second fiscal quarter, said earnings fell 36 percent to $3.7 million from $5.8 million. Earnings per share for the seventh-largest investment holding company were 34 cents, down from 67 cents a year ago when fewer shares were outstanding. Revenue was unchanged at $253 million.

For the first half of its fiscal year, Paine Webber said earnings were $10.7 million ($1.02 a share), down 33 percent from $16 million ($1.94). Revenue was $531 million, up from $522 million.

R.J. Reynolds Industries Inc. had a 1.7 percent lower profits in the first quarter in spite of a 3 1/2 percent gain in sales.

Net income was $185 million ($1.69 a share) on sales of $2.868 billion compared with $188 million ($1.72) a year earlier on sales of $2.77 billion. Domestic tobacco sales were $953 million, up from $859 million a year earlier. Foreign tobacco sales slipped to $528 million from $551 million. Food and beverage and transportation sales were higher but energy sales were down a little.

Lockheed Corp. earned $2.18 a share in the first quarter on continuing operations, up from $1.92 a year ago.

However, overall net income a year ago, including that from the discontinued TriStar airliner program, was $2.33 a share.

Net income in the latest period was $37.5 million against $36.3 million. Sales dropped to $1.144 billion from $1.149 billion.