Texas Gov. George W. Bush yesterday reversed plans to have several wealthy backers underwrite his participation in an Iowa straw poll next month, ordering his campaign--flush with a record $30 million in the bank--to pay the costs itself after Republican rivals questioned the arrangement.

Bush's about-face came on the same day he agreed to reveal the names of the "Pioneers," the charter members in his unprecedented program for those who raised $100,000 or more. The campaign had refused for weeks to identify the group but last night released a list of 115 names--a Texas-heavy group that also features several Bush family members, Michigan Gov. John Engler, Colorado Gov. Bill Owens and several corporate CEOs. Together, they raised more than $11.5 million of the record $37 million Bush has collected.

The twin moves by Bush marked an effort to put to rest two controversies over the role of big-money donors in his presidential bid--an effort that is already the best-funded primary campaign in history.

In Iowa, Bush has spent heavily to win next month's Ames straw poll, bidding $43,500 to rent prime space just outside the hall where the balloting will take place and hoping to attract 5,000 backers to the $25-a-person event. Although contributions to federal candidates are limited to $1,000 a person, the Bush campaign asked six contributors who had already given the maximum to underwrite the Iowa effort by writing checks directly to the Iowa Republican Party.

But GOP candidate Steve Forbes's campaign insisted that was a violation of federal campaign law, since the spending was clearly designed to benefit Bush's presidential effort. Late yesterday Bush communications director Karen Hughes said Bush--"to remove any question or doubt"--had ordered the campaign to pay the $50,000. That total reflects the prime space outside the straw poll as well as 260 tickets for the event.

Four of the six big givers who wrote checks to help Bush in Iowa were also on the Pioneer list: Bradford L. Freeman, the Bush friend who is leading his California fund-raising; Michigan businessmen Heinz C. Prechter and C. Michael Kojaian, both major backers of Engler; and Texas oilman Louis A. Beecherl.

Characterizing the Pioneers as a collection of "my best friends" and longtime supporters, Bush agreed to release their names after a Texas campaign finance watchdog group, Texans for Public Justice, sent him a letter yesterday charging that "the coordinated use of money-bundling Pioneers to amass such large sums of money evades the spirit of the Federal Election Campaign Act."

Even so, the list released yesterday of those who have made their $100,000 goal only hinted at the full scope of the Pioneers program, which sources said has enrolled more than 250 individuals hoping to collect six figures for Bush. "There's another group that maybe has raised $30,000, $40,000 or $50,000 toward their goal," said one Pioneer last night. "So that's millions more dollars right there."

The ambitious program--which got its name at a group bull session as campaign strategists met earlier this year--represents the broadest effort of its sort ever tried by a presidential campaign. Vice President Gore's operation, for example, seeks to enroll solicitors who pledge to collect $50,000 or more.

Texas is disproportionately represented on the Pioneer list: 56 of the 115 are from Bush's home state, including local notables such as State Sen. Teel Bivins, Enron Corp. Chairman Kenneth Lay, and University of Texas regent A.W. "Dub" Riter Jr., a managing partner in Pinstripe Investments.

But the roster also features key GOP fund-raisers from across the country, including Washington lobbying and business powerhouses such as Wayne L. Berman and Peter Terpeluk Jr., members of Congress such as Reps. Joe Barton (R-Tex.) and Jennifer Dunn (R-Wash.), corporate titans such as American International Group CEO Hank Greenberg, and Bush family members such as sister Doro Koch and uncle Jonathan Bush. Eight were from Florida, governed by Bush brother Jeb, and eight more are from the District and Virginia.

There was one key omission, however. Although Bush said at a news conference yesterday that he believed his brother Marvin rated Pioneer status, last night's list left him off. "I think he's a Pioneer," the governor said. "If he's not, we need to expose that he's not."

Staff writer John Mintz contributed to this report.

CAPTION: George W. Bush calls the "Pioneers," an unprecedented program for those who raised $100,000 or more for the campaign, a collection of friends.