PHILADELPHIA (AP) _ Corn that resists pesticides and herbicides. Soybeans that are heart-healthy like olive oil. Coffee beans that don't need to have caffeine removed because they're genetically programmed to grow with less caffeine.

All are possibilities from a new gene-altering technique known as chimeraplasty, billed as a potential treatment for up to 80 percent of human genetic diseases, but also showing promise in plants.

The technique could lead to more accurate modifications to crops and faster delivery of new seeds to farmers while also alleviating some of the problems associated with genetically altered crops, researchers say.

``It's going to be much faster, first for the farmers to see a benefit and then the consumers to see a benefit,'' said Charles J. Arntzen, president of the Boyce Thompson Institute for Plant Research at Cornell University in Ithaca, N.Y.

Arntzen conducted the research on corn with Kimeragen Inc. of suburban Philadelphia and Pioneer Hi-Bred International of Johnston, Iowa. Two articles on the research were published last week in the Proceedings of the National Academy of Sciences.

The plant research was a direct spinoff of studies involving human gene therapy and the Amish, who have a higher-than-normal rate of genetic diseases, Arntzen said.

``In humans, we're usually trying to correct a defective gene,'' he said. Defective genes in plants, however, are thrown away and replaced, he said.

Chimeraplasty allows scientists to replace small components of genes in specific areas. The research showed that plant resistance to a commonly used herbicide could be mutated into the genes of corn and the changes were inherited by a second generation of plants.

``We could insert traits in a more accurate way that we haven't had tools to do so in the past,'' said Donna Ramaeker Zahn, research communications manager for Pioneer Hi-Bred. She said the first seeds made with the technique should be available to farmers in a few years.

Arntzen said the new technique could cut the total time required to bring a new genetically engineered seed to farmers to three to five years. Using the traditional methods, eight years would be a typical timeline, he said.

The old method of genetically altering crops meant inserting a gene from another plant. The new plant had to be bred for a few generations to ensure the foreign gene had inserted properly, said Peter R. Beetham, a Kimeragen scientist. For example, the bacterial gene Bt has been inserted into corn and cotton to make the plants resist bugs.

The new method, however, uses nature's own ability to mutate to change the genes of the crop plant instead of adding a foreign gene.

``This is a way for having these changes occur at will rather than waiting for nature to do them,'' said Mike Blaese, Kimeragen's science director.

Peggy Lemaux, the head of a genetic engineering lab at the University of California, Berkeley, said the new technique should be valuable for selecting easy-to-spot traits in crops such as herbicide resistance. But she cautioned that more work needs to be done.

Science has yet to improve nutritional value, but this research may help, she said.