A Look at Genetically Engineered Vegetables

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Plant geneticist John Stommel is trying to breed an orange tomato with higher beta-carotene content.
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The trend in gardening is towards more variety.
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Seeds of the world's most unusual lettuces are safeguarded in an ARS gene bank in Salinas, CA.

A meal of soup and salad is a healthy pairing–but either component can get boring very quickly. A bowl of red lentil soup might be more exciting, though. Or how about a tossed salad of bright orange tomatoes, chocolate-colored bell pepper rings, and wedges of blue lettuce garnished with maroon carrot curls? If that sounds more like your kind of meal, then you’ll love what agricultural researchers have in store for you.

“The trend in gardening–both home and commercial–is toward more and more variety,” says Larry Kampa, Advertising Manager at Petoseed Company, Inc., a commercial hybrid vegetable breeding corporation. “The selection in size, shape, and color will only get broader.”

Though maroon carrots are still under development, seeds are available to home gardeners for many varieties of vegetables you won’t see in the supermarket any time soon. Petoseed Company, which sells its seeds for home gardening through consumer seed companies like Burpee, is especially proud of two American Award Selections it introduced in 1994: the “Big Beef” tomato and “Fanfare,” a hybrid cucumber. Fanfare produces a large, better quality yield on compact vines, while Big Beef combines good taste and continuous setting with uniform size.

Taste, shape, and most recently, color variations make the new generation of vegetables as much a coffee table accessory as part of the afternoon meal. “Purple Blush” is an eggplant with a lavender shading on white skin and a sweeter taste, while “Roly Poly” zucchini is a round squash the size of a grapefruit. Giant peppers like “Great Stuff” and “Peto Wonder” contrast beautifully with curious miniatures like “Jingle Bells” (sweet pepper) and “Bambino” eggplant.

New Strawberry Varieties

The USDA’s Agricultural Research Service has recently released two new strawberry varieties, “Redgem” and “Bountiful.” They retain much more of their original shape, color, and texture after being frozen than most other strawberries available to home gardeners, and are especially suited for preserves or for adding to pies, ice cream, and other foods.

All these new varieties represent the bottom line for plant research: an improved product. For example, one of the few nice things you can say about commercial tomatoes shipped for market across the country is that their size is uniform. Many homegrown tomatoes, such as the beefsteak, have been “rough”–oddly shaped, short, or squat. With “Big Beef,” researchers at Petoseed maintain the taste of the beefsteak, while introducing a uniform size. Other products cater to the nation’s requirements for compactness, disease resistance, flavor, and eye appeal.

At the USDA Agricultural Research Service (ARS), one primary goal is to improve food quality and safety. This may lead to research in plant productivity, disease and pest resistance, and enhancement of natural properties such as vitamin content. Doris Stanley, a writer with the ARS Information staff, discusses a project that is typical of the agency:

“Consumers and farmers are concerned with pesticide use. The EPA is taking many chemicals off the market, and of course, we’re all looking for natural replacements. Our scientists discovered that an extract from the tobacco plant will kill white fly–a significant pest in the commercial market.

“Leaf hairs on the plant contain the substance, but there isn’t enough for extraction. So, we’re now breeding tobacco plants for more leaf hairs to make extraction practical.”

Miniature Iceberg Lettuce

A new miniature iceberg lettuce is another good example of ARS research. These tennis-ball sized lettuces are true dwarfs, genetically engineered to retain the characteristics of iceberg lettuce. Dr. Edward J. Ryder, a plant geneticist, explains how this product was developed. “Most of the research for this lettuce was done by William Waycott while he was working on his PhD with us through an education training program. A real problem with iceberg lettuce is premature bolting, which happens when a growth hormone called gibberellin causes the lettuce’s flowering stalk to put on a sudden spurt of growth and break through the top of the head.”

Dr. Waycott decided to study gibberellin acid pathways, and treated an early flowering lettuce variety with ethyl methanesulfonate in an attempt to retard the bolting process. Some dwarf lettuces resulted, and the two researchers then crossed a normal lettuce cultivar (Salinas) with some of the dwarfs.

“Much to our surprise, some of the plants we got were small, perfectly formed iceberg-type lettuce. We saw an opportunity to get into the mini vegetable market, which was quite hot at the time. We took the breeding material and developed three lines, which were small and late bolting. Out of those lines, we released three varieties: Blush, which contained a natural red coloring, Mini-Green, and Icecube.”

Dr. Ryder thought the varieties would be specialty items for home gardeners and specialty seed companies. He hasn’t seen a lot of interest from commercial planters, probably because the lettuces’ slower bolting characteristic also adds about five days to development of the head. “The slower development may not be a good property for commercial crops,” says Dr. Ryder, “but this characteristic helps the home gardener because it keeps the lettuce from bolting so quickly during hot weather.”

Though these examples point out the diverse directions plant breeding research can take, Larry Kampa feels that the benefits of research are often invisible. He explains by describing a common situation: “Many times, home gardeners have to turn to pesticides because of disease problems. Unfortunately, viruses in plants are just as hard to control as viruses in humans. Gardeners usually end up controlling the vector–the insect. When research yields varieties which are disease resistant in the first place, you can consequently cut down on the pesticides.”

Plant research is almost always driven by “customer” needs–whether that customer is a commercial food processor, the American public, or local industry. “Most of us in public plant breeding programs attend the same meetings and share ideas,” says Barbara Rogers, Senior Research Associate with Texas A&M’s Department of Horticulture.

Commercial and noncommercial goals can be quite different, though, and she cites the university’s T.G. 1015Y onion as an example. “Dr. Leonard Pike (in our department) worked on the 1015 onion, selecting for mildness, a commercial benefit. However, certain chemicals in the onion help prevent cancer, and we’re now working with medical researchers from M.D. Anderson Cancer Research Center in Houston to pursue these characteristics.”

Dr. Pike is also working on the maroon carrot, still under study at A&M. Besides its more than interesting color, this carrot contains quercetin, a cancer inhibitor. Dr. Pike is trying to isolate the chemical so it can be bred commercially into available carrot varieties. Other university researchers, as well as ARS scientists, are also trying to isolate cancer inhibitors and vitamins so they can breed for their increased presence in food plants.

Though genetically mixing plant varieties solely for the sake of marketability has its detractors, research hasn’t really changed all that much in the last 80 years or so. “Most researchers use the same methods Luther Burbank introduced in 1905,” says Larry Kampa. “Traditional techniques will probably account for 99% of new vegetable breeding for the next ten years, and then we’ll likely see a move to genetic engineering.”

Is Genetic Engineering Safe?

He understands that not all consumers feel comfortable with the new technology, but believes the future lies in this direction.

“We’re very early in this process, but any actual danger is probably exaggerated. If we remember that the goal of agriculture is to grow a product, it’s easier to see that responsible family farms and corporations aren’t going to grow something dangerous.” He goes on to explain that genetic breeding moves the gene directly into the plant, rather than relying on pollen crosses as we do now. “The idea is still the same, except the work is on a molecular level.”

Dr. James Maryanski, Biotechnology Strategic Manager at the Food and Drug Administration, believes that genetic engineering will be the plant breeding technique of the future. But he also feels that some concerns about genetic engineering are valid.

“People ask if genetic engineering can produce unexpected results or surprises– and the answer is ‘yes.’ Still, we need to remember that this can happen when we use traditional techniques as well. The situation we’re more concerned with at the PDA is when new substances are introduced into a food…. This might happen when proteins are manipulated to form new combinations. That product would need to go through an additive approval process with the PDA.”

“What really raises my eyebrows is what the public has typically ignored,” says Jim McCamant, editor of the AgBiotech Stock Letter. “We have a number of companies and individuals who have modified traditional breeding through what’s called somo clonal variation. This technique forces random mutations, then incorporates them into plants by traditional breeding methods. The process is simpler than genetic engineering, and riskier.”

The mere thought of scientists randomly synthesizing proteins that will be making their planetary debut is enough to cause an overnight health advocate’s stampede on Washington, but Dr. Maryanski tried to quiet their fears.

“At the molecular level, researchers may well be looking at specific enzymes or proteins. Our guidelines consider whether a particular substance is already in the food supply and is just being moved. This could be a protein moved from one variety to another, or taken from another species. In that case, we’d feel there was little need for concern.”

He does admit that another concern is with potential allergens. “There are foods we know many people are allergic to, such as nuts or wheat, generally through the proteins they contain. We would raise a flag if we saw one of those proteins transferred to a food which normally doesn’t contain it. The producer would have to demonstrate scientifically that the protein wasn’t the allergen, or else label the food product for the consumer.”

He adds that no commercial foods on the market have been altered this way. “On the other hand, one of the exciting aspects of genetic engineering is the potential to breed out allergens. The Japanese are doing some work in this area, developing a rice that is less allergenic than current varieties. We might also be able to breed out naturally occurring toxins as well.”

Larry Kampa believes the technique offers real breakthroughs in disease and pest resistance. “We may not need pesticides anymore–and we all know the dangers of pesticide use.” He adds, “Ultimately, we’re a risk-benefit society, and consumers will drive the choices.”

Genetically Engineered Tomatoes

Jim McCamant points out that biotechnology is still a small industry. Nevertheless, current research is showing some intriguing results. “Genetic engineering is particularly valuable when it’s impossible to breed a trait into a plant naturally,” he says. For instance, the Calgene Company’s “Flavr Savr,” a genetically engineered tomato, should help to end mushiness in store-bought tomatoes within a few years.

“Growers can pick tomatoes when they’re becoming ripe, rather than when they’re green, by turning off the gene which causes softening and rot,” explains McCamant. “Genes are expressed through messenger RNA, and if you have two pieces of RNA which are exact opposites, they’ll bind and block each other. A certain gene in the tomato produces an enzyme which causes the tomato to break down. When you introduce a reverse copy of that gene, you turn it off.”

The Flavr Savr isn’t a Twinkie, it does eventually break down, but shippers have another two or three weeks to get a riper product to the stores before it does. A number of people are looking at the same sort of technology to help with fresh berries–notoriously difficult to ship.

Though Calgene has pursued FDA approval for its Flavr Savr tomato, a gray area exists in plant research. Dr. Maryanski explains that Calgene came to them before FDA guidelines were available. “Calgene did not create a new substance by merely turning off an existing gene. Where the FDA will more likely come in is when producers begin to make health claims for their improved products.”

ARS’s Dr. Ryder acknowledges the concerns expressed by several groups and feels that genetic engineering research does need care. “But that’s true even in normal breeding sequences. The USDA released a potato variety 20 years ago (through normal breeding techniques), but when biologists ran tests on it, they discovered a higher percentage of alkaloid present than in normal potato varieties. Because alkaloids are poisonous, the potato was withdrawn from the market.”

Dr. Ryder doesn’t see substantial differences between the two procedures. “In my opinion, this will be a tool, and we’ll use it the way we use other tools. I don’t think genetic engineering will be either as wonderful or as bad as proponents or opponents envision it.”

Though Dr. Ryder thinks we’ll probably see some sensational things like bringing in a gene from a distantly related crop, he says that even proponents of genetic engineering have seen that the technique isn’t the panacea they thought it was.

“It isn’t easy, for one thing,” he says. “Part of the way a gene works is through its background and environment. When you take a gene from its normal background, it doesn’t work as well.”

Genetic engineering won’t be responsible for most of the new vegetable varieties we’ll see in the next few years. Companies like Petoseed also look seriously at native crops in other parts of the world that can be grown successfully in the United States.

“This country’s hot pepper craze shows how this works,” says Larry Kampa. “Peppers which have been available in other countries for years are just now being introduced to this country.”
Similarly, USDA scientists are investigating fruits such as bruas, medang, langsat, terap, and mata kuching from Malaysia, where they’re commonplace. These were the most promising specimens of 85 collected by a research team searching for new fruit, nut, and vegetable species that might grow in the western hemisphere.

Ethnobotonist David E. Williams recently collected hirsuta, or hairy, peanuts from Mexico for breeding research through ARS. Hairy peanuts have both drought and pest resistance, but their superior flavor is what consumers will value. Unfortunately, they mature late and have lower yields, then must be harvested by hand–all significant drawbacks to commercial farming. Research, and breeding, will be necessary to get this peanut on the market.

Obviously, new plant varieties will reach consumers in a number of ways. Some vegetables may not be a viable home gardening product, especially if they grow only in certain regions of the country. Other varieties, bred to meet the demands of shipping and handling, aren’t even desired. For instance, who would want to grow the thick-walled commercial tomato in a home garden?

Universities often work to breed products especially suited to their state’s agricultural needs. When they develop appropriate products, they’ll seek plant variety protection (similar to a patent) through the federal government, then maintain the purity of that product by selling it to a company with a sublicense for the seed. In turn, they receive royalties from the company, and the seed can then find its way into home gardens.

ARS, on the other hand, doesn’t usually seek plant variety protection. When its researchers are satisfied that a germ plasm line is breeding true, they offer the variety to nurseries and breeders free of charge. From there, it will make its way to home gardeners.

What’s on the Way?

Regardless of the way new vegetable varieties come to the consumer, the future seems likely to bring us more diversity than ever. In the next few years, we may see some of these new products:

–an orange tomato, being bred by ARS for higher beta-carotene content.

–strawberries high in ellagic acid, which medical studies have shown to inhibit the start of cancer.

–“popbeans” called nunas, which burst and expand when heated rapidly. Currently grown only at high elevations, they have a nutty taste and high fiber content.

–plumcots, which have an apricot’s flavor and a plum’s firmness.

Home gardeners may even find interesting new ways to grow their vegetables. Research at ARS has shown that the color of mulch can increase the size and quality of a vegetable. Tomatoes favor red mulch, while potatoes and green peppers grow better with white mulch.

Your imagination will have to be especially vivid to stay ahead of the very real possibilities in future plant breeding. White asparagus on a bed of purple lettuce, really ripe strawberries year-round, orange-fleshed cucumbers…they may be in your garden or on a grocery shelf within a few years, along with disease and pest resistant foods grown without pesticides.

And of course, there’s still that store-bought tomato to perfect!

Sample Seed Companies

Brinker-Orsetti Seed Co.
2339A Technology Parkway
Hollister, CA 95023

Pybas Seed Co.
P.O. Box 868
Santa Maria, CA 93456

(Both of the above companies sell the miniature iceberg lettuces.)

W. Atlee Burpee & Co.
300 Park Avenue
Warminster, PA 18974

Johnny’s Selected Seeds
Foss Hill Road
Albion, ME 04910-9731

Orol Ledden and Sons
P.O. Box 7
Sewell, NY 08080

A Question of Safety

You know you
won’t glow in the dark after eating genetically altered products, but
you’re not alone if you’re concerned about their safety. Here are some
questions we might consider:

1. Can
something unexpected occur? The World Health Organization, National
Academy of Sciences, FDA, and other scientific organizations concur that
unexpected effects happen with traditional breeding techniques and
shouldn’t occur anymore often through genetic engineering.

genetic engineering is most useful when it’s used to produce changes
that can’t occur naturally, like taking a desirable trait from one plant
species and inserting it into another. In addition, a gene works
through its background and invironment; take it out of its normal
background, and it may not function the same way.

Could consumers get sick through this process? If proteins from peanuts
(a common allergen) were transferred to rice, an unsuspecting consumer
could eat the new rice and suffer allergic reactions. For that reason,
foods that have been altered in this way will require FDA labeling. Keep
in mind, too, that genetic engineering may be used eventually to breed
out common allergens.

3. Can the
nutritional content of a food be altered? Researchers are trying to
breed greater quantities of desirable chemicals into foods, whether they
be vitamins, antioxidants, or proteins. Examples are carrots with extra
beta carotene and strawberries with cancer-protective ellagic acid. As
plants are bred to contain increased amounts of healthy substances, the
FDA may need to label them the way they do other products that make
health claims.

Though scientists are
currently concerned with shipping properties and extending produce shelf
life, new research will undoubtedly raise other questions, such as:

What will we do about using genetically engineered foods further in the
production chain? Will soups, sauces, and frozen dinners use
ingredients that have been altered enough to require FDA labeling?

What will happen if wild varieties of a food plant acquire a
genetically engineered trait through natural cross-breeding? An
engineered trait like pest resistance may be beneficial in food plants
but undesirable for wild ones.

scientists believe researchers should conduct field tests that will show
how genetically engineered crops interact with existing plants, before
going any further.

C. What are the ethical considerations of transferring animal proteins to plants via genetic engineering?

What happens to our nutrition tables and balanced diets after foods are
bred to contain more vitamins or other desirable traits?

are questions still under debate by scientific organizations. They hope
to establish guidelines before researchers get far enough along to need

1. Dr. James Maryanski
2. Dr. Edward J. Ryder
1. “Engineered Foods: Coming Soon to a Supermarket Near You,” by Barbara Jacob; Vitality, April 1994.
2. “How to Eat for a Longer Life,” by Gail A. Levey, R.D.; Parade Magazine, November 14, 1993.
3. “Genetically Engineered Foods: Fears and Facts,” an interview with
James Maryanski by FDA consumer writer Mary Alice Sudduth; The 1994
Information Please Almanac.

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