KIEV, U.S.S.R. -- On the eve of the Ukraine's referendum to declare independence from the Soviet Union, officials of the republic have significantly scaled down their plans to create a powerful Ukrainian army.
Leonid M. Kravchuk, the Ukrainian leader who is the front-runner to be elected president in the balloting today, has steadily reduced his talking estimate of an independent army from more than 400,000 members to about 90,000.
At the same time, parliamentary and military officials of the republic stressed yesterday that they had just joined a tentative agreement with other republics and the Kremlin pledging that while independent armies of self-defense could be created by the republics, there remained a need for a collective strategic military force run by the republic and union authorities.
The conciliatory moves appeared to be intended to reassure the world, and especially nervous neighbors like Poland and Germany, against fears that the Ukraine might be militaristic in its independence and to begin facing the financial burdens of creating a fledgling nation from such a crucial part of the fading Soviet Union.
A 420,000-strong military is a theoretical maximum, while 90,000 is the most that could be afforded initially, officials acknowledge.
In fully breaking away from the crumbling Soviet Union, the Ukraine would present the strongest evidence to date that there will be no return to some sort of altered but still centrally powerful union, as President Mikhail S. Gorbachev hopes.
"This may be the spike that does it," a Western diplomat said of the Soviet Union's fate when the Ukrainian vote is counted.
The Ukraine would be taking with it about one-fifth of the Soviet Union's population, as well as one-fifth of its industrial and agricultural output. But officials already are stressing the need to maintain and improve economic ties with such individual republics as Russia, and to do so by establishing its own plans for the fast introduction of market economics.
By far, the overriding problem for an independent Ukraine will be the economy -- threadbare after Communist management.
Its farm produce is valuable, but it relies heavily on Russian oil and gas, and it could suffer fast bankruptcy if existing interrepublic commitments do not provide enough protection when facing the possibility of "open market" oil prices from Russia.
With about three-fifths of the population of 52 million eligible to vote, Ukrainians are considered certain to register overwhelming approval of the independence declaration adopted by Parliament.
In the ballot for the presidency, Mr. Kravchuk, the republic's most recent Communist chief, is rated as likely to come in first, by most estimates. But it was not clear yesterday whether he would win a majority or have to face a runoff Dec. 15 against the runner-up from the field of six candidates.