Reginald Jones, chairman and chief executive officer of General Electric, urged American companies today to increase expenditures for research and development and to find ways to improve productivity, adding that he was startled by GE's foreign competitors.

Jones said GE is committed to research and development, which economists say ultimately figures into productivity. He said GE's total research and development expenditures last year exceeded the 1978 level of $1.27 billion by 13 percent and that company expenditures increased by more than 20 percent.

Further increases are planned this year, including a $50 million expansion of GE's research and development center in Schenectady, NY.

Even so, Jones said he was startled to learn that some of GE's Japanese competitors have notched productivity gains of 10 percent in a single year. He said GE is forming a corporate production and operating services unit to work with all of the company's operating divisions in an effort to improve productivity.

Jones announced GE's unaudited financial results for 1979, which showed substantial growth in sales and earnings. Sales were about $22.45 billion, up 14 percent from 1978. Net earnings were $1.4 billion ($6.20 per share), up 15 percent.

Fourth quarter earnings were about $382 million ($1.68), up 5 percent from the year-ago quarter on sales of $6.13 billion.

Other corporate earnings reports, gathered from news services:

Procter & Gamble, the soap and household products company, reported a 13 percent rise in profit for the first half of the fiscal year and a gain of 15 percent in the second quarter.

Profit for the second quarter was $146.66 million ($1.77) on sales of $2.622 billion compared with $127.1 million ($1.54) a year earlier on sales of $2.249 billion.

The first half profit was $332.33 million ($4.02) on sales of $5.286 billion compared with $294.01 million ($3.56) a year ago on sales of $4.535 billion.

National Distillers & Chemical Corp. reported it earned $4.04 a share last year, up from $3.23 in 1979, due largely to gains in chemicals. Sales topped $2 billion for the first time.

Net income for the year was $135.75 million on sales of $2.115 billion from $106.81 million on sales of $1.857 billion.

Fourth quarter profit also rose but more moderately to 96 cents a share from 91 cents a year earlier. Net income was $32.57 million on sales of $558.7 million, compared with net income of $30.74 million on sales of $526.1 million.

St. Regis Paper Co. had a 23.6 percent gain in profit to $4.87 a share last year from $3.94 in 1978 in spite of a slowdown in its construction products business and the discontinuance of some operations.

However, fourth quarter profit was up only 4.6 percent at $1.13 a share from $1.08 a year go.

Net income for the year was $158.49 million on revenues of $2.534 billion compared with $126.51 million in 1978 on sales of $2.336 billion. Final quarter net was $36.8 million on sales of $671.07 million compared with $34.9 million a year earlier on sales of $604.01 million.