With hopes of developing apple trees that need fewer chemical pesticides to control insect attacks, researchers from the University of California, Davis, and a Modesto biotechnology company recently planted genetically engineered apple seedlings in an Oakdale nursery. The planting represents the first known field trial of "transgenic" apple trees -- seedlings that carry genes not normally found in the apple tree. Since 1987, more than 300 field trials of transgenic plants have been completed or are in progress nationwide, according to the U.S. Department of Agriculture. "We want to see what types of variabilities occur among these apple trees when they are planted in nursery rows as commercial trees would be," said Abhaya Dandekar, an associate professor of pomology at UC Davis. "This will give us the opportunity to evaluate the vigor, size and performance of the trees in the field." Dandekar, who is working with Plant Research Laboratory (PRL) of Modesto, has been doing laboratory studies on gene transfer in apple trees for the past three years. The young apple trees carry a gene for insect resistance and several marker genes, which simply serve as indicators that a foreign gene has been transferred and incorporated into the apple tree. In the laboratory, genes derived from certain bacteria were introduced into other bacteria, which were then used to infect the apple leaf segments. In this way the genes were transferred into the genetic material of the apple trees. In addition to reducing the need for chemical pesticides, the project, if successful, should provide considerable economic advantages to growers, Dandekar said. "The apple is a very interesting model to work with because it has a shorter life cycle than many other fruit and nut trees," he explained. "And quite a lot of basic genetic research has been done on the apple." From an economic aspect, the apple also is an ideal fruit to study, since the apple crop's annual nationwide commercial value exceeds $1 billion. California is the third-ranked apple-producing state in the nation. During the next six months, PRL will plant several hundred 4-inch-tall apple seedlings in the Burchell Nurseries test plot, which is less than one-fifth of an acre in size. The seedlings are the "Greensleeves" variety of the Golden Delicious apple and are planted in the field using a procedure patented by PRL. Since apple trees don't flower for several years, there is no chance for genetically altered pollen to spread to neighboring plants during the field trial. Any premature blossoms will be removed before opening, and the transgenic test plot will be bordered by two rows of non-transgenic apple trees and a fence. The experimental trees will be removed before they reach the full flowering and fruiting stage. Dandekar's research is collaboratively funded by Plant Research Laboratory and the California Department of Commerce's Competitive Technology Program. In a related research project, Dandekar is also working with the U.S. Department of Agriculture laboratory in Fresno to study the efficiency of transgenic apple plants in providing resistance to apple pests.