For Release March 5, 2006

Where Has My Favorite Tomato Variety Gone?

by Chuck Otte, Geary County Extension Agent

It all started a couple of weeks ago when a caller wanted some help in finding where to buy some seeds of a favorite tomato variety. What should have been an easy task, so I thought, turned into an ever increasing mystery that lasted for days. I was finally able to find one of the varieties he was looking for, but the second simply wasn't to be found.

The answer to the mystery includes two basic themes: genetics and dollars. For many years, virtually all vegetable varieties were what plant breeders call "pure lines". They came from standard crosses and the superior plants were selected and selected and selected for about 9 generations until they were breeding true. In other words, there was no variation within the seedlings grown from the fruit and from one generation to the next. Maintaining pure lines is relatively simple. You make sure that no stray pollen fertilizes the flower, you collect the fruit and process the seeds. This is what gardeners had done for centuries.

Then a monk by the name of Gregor Mendel came along and discovered genes and what they do. It wasn't more than a century or so after that, that plant breeders discovered something called hybrid vigor. When two pure lines are crossed, the offspring, what geneticists call the F1, will all be identical, and they will often have superior performance when compared to the two parental lines. In essence 1 plus 1 equals 3. Improved production, improved disease resistance and improved quality are all factors that came into play with hybridization.

But the problem with hybrids is that if you keep the seed from those hybrid fruit, the F1, and plant it out, you will start to see variation. In this second generation, or F2, you would expect a certain percentage to look like each of the parent lines and the rest to look something like the previous year's crop. But each year further out you go, you will start to find fewer and fewer that looked like the original. So while the F1 hybrid may have been very desirable, you soon wind up with nothing like that, and often many inferior plants.

Over the past few decades, many of the "new and improved" vegetable varieties that gardeners have been planting have been hybrids. Sure, if you look around you can still find the good old pure lines, and while they may still taste better, they often don't have the disease resistance, or other improved features of the newer hybrids. But seed production can be highly labor intensive and very expensive. Small operations have been bought up by larger operations and we have gotten to the point where vegetable seed production is being done by only a handful of companies.

Because of the cost and expense of maintaining a lot of different hybrid lines and their pure line parents, these companies are eliminating older hybrids and simply producing what they feel are the best and most popular, i.e., profitable. The bottom line is, that if a favorite vegetable variety of yours was a hybrid and you can't find it now, you probably won't. If, however, it was an older pure line, I can probably find you a seed source as there are numerous groups working to preserve many of those older heirloom lines.

Unfortunately, I don't think that many individuals, or groups will go through the trouble to maintain some of the older, and not so old, hybrids. If you are looking for a listing of recommended vegetable varieties, however, we have a list from the K-State horticulturists that we can provide.


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