Engineering the Ideal Christmas Tree

December 20, 1992|By YVONNE BASKIN

ENCINITAS, CALIFORNIA — Encinitas, California.--In a greenhouse in Madison, Wisconsin, a row of ordinary-looking six-inch spruce trees may represent the ghosts of Christmas future. These tiny trees are clones of superior white spruces, fortified with a bacterial gene for pest resistance and rooted in soil after long incubation in a lab dish.

They represent only the second success scientists have had in regrowing conifers (cone-bearing trees) from genetically engineered embryos. The first came last year at Michigan Technological University with a European larch, and similar manipulations of fir and pine are close behind.

''The work with spruce is a model that will give us ideas of which buttons to push to do genetic manipulations on more commercially important conifers like Douglas fir and various pines,'' says David Ellis, a scientist in horticulture at the University of Wisconsin, who is reporting the success with spruce in the scientific journal Bio/Technology in January.

Most of the interest in forest biotechnology comes from the timber industry, but Dr. Ellis and others are quick to reel off ''pie in the sky'' ideas with potential for the Christmas tree market -- tinkering with genes to make trees bushier, more symmetrical, faster growing, greener, hardier.

''We even joke about getting a tree that glows in the dark,'' says Dr. Ellis, who once succeeded in getting a firefly luminescence gene to work in Douglas fir cells. The cells carrying the foreign genes -- scientists call them ''transformed'' cells -- could not be .. coaxed into sprouting shoots and roots and growing into trees, however.

Fanciful as some of this sounds, the $1.2 billion Christmas-tree industry is counting on science to keep living conifers competitive with the plastic kind. And researchers in forestry and ornamental horticulture are increasingly supplementing traditional tree-breeding programs with new techniques such as cloning, tissue culture and genetic engineering.

The problem for Christmas-tree growers is that few Americans besides the ''Peanuts'' character Charlie Brown seem willing to settle for a scruffy little, needle-shedding pine tree these days. And many cities do not offer programs to collect, chip and recycle trees after the holidays. So the search for convenience and perfection has led half of all American families who display Christmas trees to purchase artificial ones.

''This year we're projecting sales of 36.3 million trees,'' says Joan Geiger of the National Christmas Tree Association. ''As of last Christmas there were 36.3 million artificial trees in use. So we'd like to stay even with that industry.'' Scotch pine is the top seller, with 36 percent of the market. Douglas fir is second at 20 percent. Assorted other pines, firs, spruces and cedars make up the rest.

The modern Christmas-tree industry got its start in the 1960s and grew rapidly through the early 1980s, when many people were lured into tree farming as a tax shelter. Today, there are about 15,000 growers in the business and too many trees on the market.

''The industry is in its infancy and it's never faced an oversupply mode until now,'' says Bryan Ostlund, executive secretary of the Pacific Northwest Christmas Tree Association. ''We really haven't had to turn to technology in the past because the trees basically sold themselves.

''But that's not the case anymore. It's a very competitive business and it's the quality trees that are in the most demand.''

During the past decade, Mr. Ostlund's organization has begun to support research to help growers in the Pacific Northwest achieve that edge in quality in their Douglas firs. One tack has been to develop a way to generate identical copies or clones of superior trees from branch cuttings.

In traditional breeding, each offspring gets a novel mixture of genes, half from each parent. Desirable traits in a parent often do not ''breed true'' or show up in every offspring. Cloning has the advantage of producing genetic carbon copies of a single parent.

With plants like geraniums or poinsettias, cloning is as easy as sticking a section of stem in soil and letting it take root. Getting roots to sprout on Douglas fir cuttings, however, has taken William Proebsting of Oregon State University more than a decade of research and some timely applications of plant hormones called auxins.

Every January now, Oregon growers send Dr. Proebsting hundreds of cuttings of branch tips from their finest Douglas firs. If 80 percent or more of the cuttings from a single tree sprout roots, Dr. Proebsting takes them to the next stage. These cuttings or clones spend two years in a nursery bed, then another six years growing at the campus horticultural farm. After eight years, if a set of clones passes muster for ''color, vigor, symmetry and upright growth,'' they are trimmed into a hedgerow to make them bushy. Then hundreds of tips are cut from these and sent to commercial nurserymen to propagate and supply to Christmas-tree growers.

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