What’s in a Seed: Plant Genetics versus Genetic Engineering

Thanks to Keith Stewart for this guest post. Keith is a writer and farmer in the Hudson Valley. He owns and manages Keith’s Farm, a certified organic farm and CSA. He’s the author of It’s a Long Road to a Tomato: Tales of an Organic Farmer Who Quit the Big City for the (Not So) Simple Life. You can find him at the Union Square Green Market in New York City, where he sells his produce (both legible and edible) on Wednesdays and Saturdays.


These days heirlooms are all the rage. Especially, heirloom tomatoes. At our Union Square Greenmarket stand in Manhattan, this past summer, Brandywines, Cherokee Purples and Striped Germans sold for 50% more than the regular hybrid tomatoes that we also grow. Customers seemed eager to buy our heirlooms, which certainly do taste good (and, incidentally, are more finicky to grow and difficult to transport), but I often wondered if they knew just what it was they were forking out that extra cash for. Here’s a breakdown of the three types of seeds farmers use and what the differences are between them.


In a nut shell, heirlooms are varieties of vegetables and fruits that have been around for at least 50 years. And they are always open-pollinated. This means they are largely a product of evolution and or selection of preferred traits (like good taste, abundant produce and pretty colors) by humans over time. They grow true to type and produce viable seed when randomly mated within their own variety. This means you can save their seed and replant it.



Hybrids are a little different from open-pollinated plants, but they’re still natural genetics at work. They are created by crossing, in a controlled environment, two or more different varieties, usually within the same species. The result can be a superior plant that shares some of the positive traits of each parent. Seed from hybrid plants is rarely saved, however, because it is usually sterile or, at best, unpredictable. In the world of mammals, think of what happens when you mate a horse and a donkey: You get a mule — good for carrying heavy loads perhaps, but always sterile. Vegetables grown from hybrid seeds have been a staple of our food system for more than 50 years. They’re nothing to be afraid of.

Genetically Modified

Genetically modified seeds are a totally different bag of beans and there are several reasons to be concerned about them. Practitioners of genetic modification will tell you that they are just following in a long tradition of human plant breeding and selection. What they don’t tell you is that their gene-splicing techniques are unlike any form of propagation that has taken place before.

In the first place, genetic modification of plants does not rely on natural reproductive methods which have been used to create hybrids and open-pollinated seeds in the past. Instead, the approach is decidedly non-sexual.

Two principal techniques are employed. The first, and currently the most common method, relies on the use of an infectious bacteria to insert foreign genes into a plant’s cells. The second approach, which is perhaps more quintessentially American, uses a gene gun (a sort of air gun) to shoot tiny particles of gold, coated with foreign genetic material, into the cells of the subject plant. Frequently, genes from totally different species are forcibly conjoined. In the case of the Calgene tomato, genes from a flounder were spliced into a tomato. Sound a bit fishy?

Many scientists believe that transgenic plants are a risky proposition. Yet, because of pressure from such behemoths as Monsanto, they are usually released into the environment with very little long term testing or government oversight. Who knows what havoc they might wreak on the earth’s natural systems? Concerns include: the introduction of new toxins and allergens into our food system; the contamination of other, related food crops and wild plant species; the development of super competitive weeds and insects; and a reduction in biodiversity. So far, the use of genetically modified corn and soy beans has led to greater use of agricultural chemicals, not less, and, generally, yields are no higher!

Finally, the widespread use of genetically modified crops will almost certainly lead to further consolidation within the agribusiness community and ultimately to patented ownership and control of the foods we eat. Given the food industry’s recent record and apparent unconcern for human health, that really is scary.

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