WASHINGTON (AP) _ A California biotechnology company agreed today to plead guilty to conspiring with the Brown & Williamson tobacco company to grow and improve tobacco with a high nicotine content.

The criminal information filed here against DNA Plant Technology Corp. of Oakland was the first charge filed in the Justice Department's broad investigation of the tobacco industry. The company agreed to cooperate with the investigation.

The government cited the tobacco company as an unindicted coconspirator and refused to name it. But individuals familiar with the investigation said it was Brown & Williamson Tobacco Corp., the third largest U.S. cigarette company which makes the Kool, Viceroy and Raleigh brands.

Late last year, 18 Brazilian farmers openly acknowledged to The Associated Press that they are growing high-nicotine leaf by the ton, and many said they have been growing it for more than five years. The AP reported that the high-nicotine tobacco _ called crazy tobacco or fumo louco by the growers _ was the offspring of a genetically altered plant created in U.S. laboratories for Brown & Williamson.

The tobacco company and the biotech firm devised a scheme to secretly improve the high-nicotine tobacco in Brazil and other foreign countries because commercial growing of such high-nicotine tobacco is banned in this country by federal regulations, the government said.

The tobacco company's goal was to develop a reliable source of high-nicotine tobacco that it could use to control and manipulate the nicotine levels of its cigarettes, the government said. Higher levels of nicotine are thought to help ``hook'' smokers on cigarettes.

The government charged that in 1983 the biotech company, known as DNAP, contracted with the tobacco company, which gave it a strain of flue-cured tobacco, code-named Y-1, to grow and improve. Y-1 had a nicotine level of about 6 percent, about twice the normal nicotine level of flue-cured tobacco, the Justice Department said.

One goal specified in the contract was alteration of chemical composition of tobacco lines which ``could include production of lines with elevated nicotine content,'' court papers said. In April 1985, an expanded contract listed the first goal as ``(d)evelopment of commercial high nicotine varieties'' of tobacco.

DNAP was charged with one misdemeanor count of conspiracy to violate the Tobacco Seed Export law, which prohibits export of tobacco seed without a permit. The law prohibiting such exports was repealed in 1991.

On numerous occasions between 1984 and 1991, the Justice Department said, employees of the two companies illegally exported Y-1 and other tobacco seeds to Brazil and other countries, including Nicaragua, Honduras, Chile, Nigeria, Costa Rica, Argentina, Zimbabwe and Canada. The aim was to explore whether these were good locations for growing Y-1 tobacco.

The government said employees of the two companies illegally shipped the seed by air express, courier and by smuggling it themselves when traveling to Brazil.

During the Food and Drug Administration's tobacco investigation in 1994, DNAP concealed information about its contract with the tobacco company and the export of tobacco seeds, the court documents charged.

In 1994, Food and Drug Commissioner David Kessler told a House subcommittee that federal investigators found Y-1 growing in Brazil and used in some Brown and Williamson brands sold here after B&W had told the agency that higher-nicotine tobacco breeding was not ``feasible.''

In 1993, B&W used the high-nicotine leaf in five U.S. cigarette brands, including three ``light'' cigarettes implied to be healthier: Viceroy King Size, Viceroy Lights King Size, Richland King Size, Richland Lights King Size and Raleigh Lights King Size, the FDA said. After the FDA announced its investigation, B&W pulled its U.S. patent application for Y-1 and removed its seeds from the National Seed Storage Laboratory.

The maximum penalty for the misdemeanor violation is a fine of $200,000 or twice the monetary gain to DNAP under the contract.