UNIVERSITY PARK, Pa. -- After nearly half a century trying to develop "the perfect Christmas tree," a researcher in Penn State's College of Agricultural Sciences admits it still doesn't exist, but claims trees are much better today than they were in 1956.

"When I started this work, the nursery owners were getting all their seed from dealers who collected seed from wild trees," says Henry Gerhold, genetics professor in the School of Forest Resources. "Trees then were in no way improved for Christmas use.

"He recalls when he was a graduate student at Penn State in the early 1950s his advisor, a professor named William Bramble, arranged to have seed from Scots pine trees imported from central Spain. Bramble had read a report saying the Spanish trees kept a pleasant green color and didn't turn yellow the way Scots pine trees from other European seed sources did.

Over time, the name Scots pine somehow evolved into "Scotch" pine here, although in Spain, the trees still are known merely as pines. Scotch pines remain one of the most popular varieties for indoor use at Christmastime. Ironically, notes Gerhold, Scots pines are not used as Christmas trees in Europe.

"I started out doing research on the trees grown from the Spanish seed," Gerhold remembers. "Using simple genetic techniques, we began improving the trees."

Penn State researchers selected trees that had the traits they wanted in a Christmas tree -- good needle characteristics, straight trunk, upswept branches, well-formed crown, nice color and fast growth -- and bred them.

"We enclose the female flowers with little cellophane bags to keep out unwanted pollen, then collect pollen from male flowers (usually on the same tree, but on other branches)," he explains. "We use a device to blow pollen into the bags with female flowers. A year and a half later we go back and collect the seeds from the cones."

Seedlings were grown from the seeds and Gerhold and his associates kept track of the offspring from parent trees. To create seed orchards, they picked out the "best" Scotch pines and removed all the trees that didn't have the desired Christmas tree characteristics. The process has been repeated numerous times, and the seed for improved trees eventually made its way to Christmas tree growers both in and out of Pennsylvania.

The same type of research was done on Douglas-fir trees and Gerhold also experimented with concolor fir, Canaan fir and Fraser fir trees. He points out that Douglas-firs are not true fir trees.

"You can bring about noticeable improvements without ever knowing what genes you are manipulating, just with selection," says Gerhold. "It's a primitive genetic technique compared to what's being done today."

What's being done today at Penn State is more complicated research into developing new propogation systems for Fraser fir and other species and increasing resistance to disease and damage caused by insects.

John Carlson, an associate professor of molecular genetics, is germinating and growing seedlings under strictly controlled conditions in a laboratory. "We are developing micropropagation protocols to mass propagate via tissue culture the best tree genotypes that local farmers would prefer to grow," he says. "This will provide better uniformity for the growers and better selection for their customers.

"With Fraser firs, there is a major problem with susceptibility to the insects balsam wooly adelgid and balsam twig aphid," Carlson adds. "The balsam twig aphid is a native pest while the balsam wooly adelgid is an exotic pest that has destroyed most stands of Fraser fir in the wild. There is no known natural resistance to these insects in the Fraser fir."

Carlson believes that genetic engineering might be used to incorporate disease resistance into Fraser fir trees, for both the Christmas tree industry and to help restore the species in the wild, but he isn't sure, with all the controversy surrounding genetic engineering, that consumers will want that. The current alternative for growers is to spray trees with pesticides and fungicides, but new regulations have banned most chemicals that are effective in controlling pests.

"We are hoping to be of some help to the Christmas tree-growing industry," says Carlson. "Perhaps a new business within Pennsylvania's green industry can be created to grow disease-resistant seedlings using tissue culture."

Can the "perfect" Christmas tree really be created? Both Gerhold and Carlson say probably not.

"But our research can result in a much better selection of trees," Carlson says. "It may mean that your family will have a much easier time finding just the right tree when you visit your favorite Christmas tree farm."

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EDITORS: Henry Gerhold can be contacted at 814-865-3281; John Carlson at 814-863-7561.

To download high-resolution image, go to http://aginfo.psu.edu/News/december01/henry.tif

Contact:

Jeff Mulhollem jjm29@psu.edu 814-863-2719 814-865-1068 fax