Kohlberg, Kravis, Roberts & Co. has launched its $20.3 billion takeover bid for tobacco and food giant RJR Nabisco Inc., a deal that if completed would be the biggest corporate acquisition in history.

Kohlberg, Kravis, a private New York investment firm, began a $90-a-share tender offer Thursday for 87 percent of RJR Nabisco's 225.3 million common shares.The move came one day after the breakdown of talks between Kohlberg, Kravis and RJR Nabisco's top management on the possibility of forming a partnership to buy RJR Nabisco, the 19th-largest U.S. industrial company.

The RJR Nabisco executives, led by Chief Executive Officer F. Ross Johnson and with the financial backing of Shearson Lehman Hutton Inc., said last week they were considering offering $75 a share, or $16.9 billion, to take RJR Nabisco private.

Although the purchase price under the executives' potential proposal was lower, analysts said the company would be stronger if current management remained with it after any transaction.

RJR Nabisco, based in Atlanta Ga., was formed by the 1985 merger of R.J. Reynolds Industries and Nabisco Brands Inc. Its many brand name products include Camel, Winston and Salem cigarettes, Ritz crackers, Oreo cookies and Del Monte canned fruits and vegetables.

Published reports said the discussions between Johnson, Kohlberg, Kravis and Shearson ended early Wednesday morning after the RJR Nabisco team rejected Kohlberg's demand for full management control over any partnership between the three groups.

Despite the breakdown in cooperation, the Kohlberg, Kravis tender offer was not overtly hostile since it was conditioned on, among other things, approval by RJR Nabisco's board.

Other conditions on the offer, which will last through Nov. 25 unless extended, included obtaining financing and tender of enough shares to give Kohlber, Kravis a majority.

As the offer began, RJR Nabisco's shares slid $2.875 to $81.875 in heavy early trading on the New York Stock Exchange, where they were the most active NYSE-listed issue.