By William Terry KelleyUniversity ofGeorgiaFor a long time, gardeners were unwilling to change tomatovarieties. What worked for their grandfather still worked forthem. And since that variety performed well, this wasn’t a badphilosophy. Probably, though, many others would have done just aswell or better.Many old tomato varieties are still in circulation. But in recentyears, many gardeners have adopted hybrid varieties that havebetter disease resistance and better yields.Even more recently, tomato growers have been faced with theever-increasing presence of tomato spotted wilt virus.Transmitted by thrips, this virus is not only the plague ofcommercial growers but is actually even worse for home gardeners.Only in the past couple of years have varieties been introducedthat have resistance to TSWV. Since then, many gardeners haveopted to go with a resistant variety to be able to grow tomatoessuccessfully.TSWV resistanceOver the past few years, there have been two varieties withresistance to TSWV: “BHN 444” and “BHN 555.” These have becomemore 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 HarrisMoran Seed Company; “BHN 640,” an improved BHN 444 from BHNGenetics; and “503,” from Seminis Seed Company.These varieties are generally only available in large seedquantities. So gardeners will find it easier to buy plants thanseed.However, in 2002, TSWV was detected to some degree in resistantvarieties. The resistance in these varieties is from a singledominant gene. In layman’s terms, this means that the resistancecan more easily be broken by the virus than if it were amulti-gene resistance trait.Fragile resistanceThe resistance in all of these varieties is the same. Therefore,when resistance is broken in one it will likely be broken in allof them.What does this mean? Primarily it means the resistant tomatoesavailable right now will probably only buy growers a little timebefore TSWV overcomes this resistance.In the meantime, we can hope that other types of resistance canbe found.Other than TSWV-resistant types, there still are an abundance oftomato varieties available.Two companies that specialize in tomatoes include Tomato GrowersSupply Company (www.tomatogrowers.com) and Totally Tomatoes(www.totallytomato.com). In all likelihood, if it’s a varietythat has been grown to any extent in gardens over the past 100years, you’ll find it in one of these catalogs.Heirlooms, novelties, hybridsThis is not to say you can’t get many of the same varieties fromother companies. And some have excellent proprietary varietiesonly they can sell. However, those specializing in tomatoes havea long list of heirloom and novelty varieties, as well as manyhybrids.For instance, have you ever heard of a white tomato? “WhiteBeauty” is only one of several white varieties available.”Cherokee Purple” has dusky, rose-purple fruit. “Green Zebra” isamber green with dark green stripes when mature. “Hillbilly” is ahuge, bicolored tomato that has yellow-orange skin with redstreaking.There are many beefsteak varieties, oxhearts, brandywines, pasteand grape tomatoes, too, and many imported from other parts ofthe world.’Mortgage Lifter’Remember “Abraham Lincoln” (the tomato, not the president)? Itwas introduced in Illinois in the 1920s. “Mortgage Lifter” is avariety Uncle Joe used to grow. Legend has it that the firstfarmer that grew it sold enough tomatoes to pay off his mortgage.There’s a difference between garden varieties and shippingtomatoes. The ones for commercial growers have been bred forshipping (including all TSWV-resistant varieties). They will stayfirm longer than garden varieties. But tomatoes will almostalways taste better when picked vine-ripe.Whether you’re looking for an old favorite, something withdisease resistance or just a novelty, though, there is a tomatoout there for you.