Bloom Control Feed
Why Save Seeds? Science of Gardening
Page 1 Page 2 Page 3

More Knowledge, Less Diversity

Until about a hundred years ago, farmers and gardeners had no understanding of genetics or patterns of inheritance. They knew only that plants, like animals, can pass on traits to their offspring through reproduction. Given that perspective, it’s pretty impressive that earlier growers managed to develop such a mind-boggling diversity of plant varieties. In the twentieth century, as theories of inheritance unfolded and the structure and function of DNA became clear, plant breeders devised new ways to bring out desired traits in a plant. These often involve hybridization, a complicated process of inbreeding and cross breeding plants that results in a particularly strong expression of some of its genes. Other, more modern methods include transgenics, the splicing of desirable genes from one species into another. (For more on hybridization and transgenics, see Three Ways to Make a New Plant.)


Exploratorium
  Saving Seeds
  Saving Seeds, Saving Culture
Learn about the Native Seeds/SEARCH seedbank, which preserves plant varieties developed by Native American farmers in the Southwestern United States.
Because there are specific methods for developing the seeds for hybrid plants, they are usually produced on a large scale by seed companies rather than by individual farmers or gardeners. Many growers today, from farmers to backyard gardeners, buy these seeds because they have lots of beneficial qualities: They may be able to withstand difficult weather conditions, have bigger fruits, or be easier to harvest. The downside is that where these commercially developed varieties are planted—whether it be in your urban window box or on a rural farm—the smaller-scale, homegrown ones aren’t. And where homegrown seeds aren’t being planted, varieties are being lost. This goes for Granny’s heirloom tomatoes, too.

As a result, most of what we plant, grow, and eat comes from just a few highly developed varieties of each of our food plants. At the garden store, you may find ten or twelve less-common carrots or onions to plant, but this doesn’t begin to match the diversity that actually exists.

 

Keeping the Story Going

“So?” you asked many paragraphs back. “If we lose a tomato or two, what’s the big deal?” Genetic diversity is a sort of insurance policy for the continuation of a species, and it’s what drives change and adaptation in the living world. In the case of garden and crop plants, diversity insures that we’ll be able to continue eating the plants we now eat.

Giant Pumpkin
Giant pumpkin growers begin their competitive season by planting specially-developed seeds.  

A field of corn, tomatoes, or any crop grown from hybrid seed is a field of very, very close relatives—much more closely related than a field of tomatoes grown from Great Grandmother’s seed. Each individual in the field of hybrids will be susceptible to the same ills, and therefore they could all be wiped out by one pest, disease, or weather incident. In 1979 and 1980, for example, the entire rice crop in India was decimated by a blight, a crisis in a country where rice is the staple. The rice crop in the region was restored when, after searching the continent, agronomists (soil and plant scientists who work on crops) found an obscure rice variety that was resistant to the disease. If farmers had not saved and grown that particular variety, it may have been much more difficult for Indian farmers to combat the blight, and the people they feed would have had to turn to other crops for sustenance. Similar situations have arisen involving many crop plants, some with less happy endings. In the case of the Irish potato famine, not only did blight wipe out most of the potatoes; the lack of food wiped out much of the population as well.

If you’re a backyard gardener growing and saving seeds from Great Grandma’s tomatoes, you’re helping to maintain the same diversity that rescued the rice crop. Saving seed has other, more personal benefits, too. By raising generations of plants, you’ll see for yourself how traits are passed on, and how you can select for the qualities you want to bring out. Over time, you can even “customize” your plants to suit your backyard conditions and your tastes. This is what growers before you have done for centuries, and everything in your garden is a genetic record of their choices. By saving and planting seed, you add your own chapter to the story.

Next

 
© Exploratorium