For a long time, gardeners were unwilling to change tomato varieties.
What worked for their grandfather still worked for them. And since that
variety performed well, this wasn't a bad philosophy. Probably, though,
many others would have done just as well or better.
Many old tomato varieties are still in circulation. But in recent
years, many gardeners have adopted hybrid varieties that have better
disease resistance and better yields.
Even more recently, tomato growers have been faced with the
ever-increasing presence of tomato spotted wilt virus. Transmitted by
thrips, this virus is not only the plague of commercial growers but is
actually even worse for home gardeners.
Only in the past couple of years have varieties been introduced that
have resistance to TSWV. Since then, many gardeners have opted to go
with a resistant variety to be able to grow tomatoes successfully.
Over the past few years, there have been two varieties with resistance
to TSWV: "BHN 444" and "BHN 555." These have become more available to
gardeners in the past year or two.
This season, for the first time, three new varieties with TSWV
resistance were released: "Amelia," also known as HMX 0800, from Harris
Moran Seed Company; "BHN 640," an improved BHN 444 from BHN Genetics;
and "503," from Seminis Seed Company.
These varieties are generally only available in large seed quantities.
So gardeners will find it easier to buy plants than seed.
However, in 2002, TSWV was detected to some degree in resistant
varieties. The resistance in these varieties is from a single dominant
gene. In layman's terms, this means that the resistance can more easily
be broken by the virus than if it were a multi-gene resistance trait.
The resistance in all of these varieties is the same. Therefore, when
resistance is broken in one it will likely be broken in all of them.
What does this mean? Primarily it means the resistant tomatoes
available right now will probably only buy growers a little time before
TSWV overcomes this resistance.
In the meantime, we can hope that other types of resistance can be
Other than TSWV-resistant types, there still are an abundance of tomato
varieties available, including heirloom and novelty varieties as well
as many hybrids
There's a difference between garden varieties and shipping tomatoes.
The ones for commercial growers have been bred for shipping (including
all TSWV-resistant varieties). They will stay firm longer than garden
varieties. But tomatoes will almost always taste better when picked
Source: William Terry Kelley,
University of Georgia
Plants and Seeds