President Daniel arap Moi has emerged from this week's national elections as a leader in his own right five years after the death of the country's larger-than-life founding father, Jomo Kenyatta.

Moi, who ran unopposed in his home constituency, had called the parliamentary elections a year early "in order to clean the political system" following a difficult administration in which he faced economic problems and political opposition. The voting for the 158 seats in the Parliament did not jeopardize his presidency since in Kenya's parliamentary system he holds that office by virtue of being leader of the Kenyan African National Union, the only legal party in the country. Yet Moi had made clear in the campaign that he was seeking a mandate from the voters.

The nearly complete returns from Monday's voting revealed some surprises, including widespread voter apathy, the retention of a higher than usual percentage of incumbent members of Parliament and the dramatic rejection of an unusually high 50 percent of incumbents by Kenya's largest ethnic group, the Kikuyu.

Kenyan political observers were at a loss to explain what the new voting developments indicate for the future of this East African country of almost 18 million people. Pro-western Kenya is of growing importance to the United States as a staging post for the planned Rapid Deployment Force.

"We expected a higher voter turnout because of the 'traitor' issue, and Moi's call to 'clean the system' was expected to wipe out a lot of incumbents," said one Kenyan political analyst who declined to be identified. "Obviously, people do not think much of these issues. People were probably interested in keeping the MPs members of Parliament who brought development into their areas."

Charles Njonjo, for two decades a controversial figure at the center of power in Kenyan politics, was denounced by Moi earlier this year as a traitor being groomed by an unnamed foreign government to take over from Moi. He was thrown out of Moi's Cabinet, suspended from the country's political party and is facing a judicial inquiry into his activities. Njonjo was the last powerful holdover from Kenyatta's days, and with his demise "Moi has eliminated his only possible competitor" for national leadership, said an analyst.

"Over the past several months, Moi has emerged as a strong leader and is in position, for the first time, to rule effectively," said a long-time British observer of Kenyan politics. Njonjo and Vice President Mwai Kibaki, both Kikuyus like Kenyatta, played significant roles in the selection of Moi's first Cabinet. Moi "will be appointing his own Cabinet for the first time," the British observer added.

As an unobtrusive vice president for 11 years until Kenyatta's death in 1978, Moi played a vital role of assuring Kenya's many minority groups of a voice in governmental decisions. Moi is a Tugen, one of several minority groups of Western Kenya grouped together by their Kalenjin language.

This election, the fifth since Kenya's independence from Britain in 1963, is the first in which Moi has been able to break free of the political structures built up during Kenyatta's 15 years of rule. Moi's first presidential election was in 1979, in the shadow of Kenyatta's death.

Still, results for 146 of the 153 constituencies counted by this evening indicated that the election witnessed as little as 27 percent of registered voters participating in some previously high-turnout urban constituencies here in the capital, and a low average of a 40 percent turnout in numerous rural districts. In 1974, voter turnout averaged 68 percent nationwide, and in 1979 it was 62 percent.

Moreover, of 138 incumbents seeking reelection, only 48, about 37 percent, lost their bids according to results so far. In 1974, a high of 64 percent of the incumbents were rejected by voters, and 58 percent lost their seats in 1979.

Significantly, the Kikuyus dramatically reversed past voting patterns and kicked out 13--more than half--of their 24 incumbent members of Parliament. Three of those defeated were in Moi's outgoing Cabinet. The Kikuyus make up 20 percent of Kenya's population.

One close observer of Kenyan politics said that in previous elections the rejection rate for incumbents was a low 20 percent in Kikuyu areas. As the dominant political group, Kikuyu incumbents in the past were able to deliver more to their districts.

"Those Kikuyu MPs close to the Moi government were turned out this time because the Kikuyu are dissatisfied with their declining role in the central government and are unhappy that the unseated incumbents did not do better in protecting Kikuyu interests," the observer added.