Why do most homegrown hybrid tomatoes and commercially grown tomatoes lack the robust flavor of yesteryear’s tomatoes? Let us look at some of the reasons behind this familiar lament.
Tomatoes are the most popular fruit or vegetable all around the globe. The worldwide demand for tomatoes and tomato products has driven plant breeders to develop tomato varieties that have large, smooth, round, uniformly colored red fruit. To make production easier and more cost effective they have also endeavored to create varieties that dependably produce heavy yields of fruit that all mature at the same time. Their goal has been to produce as many tomatoes as possible to help meet the demand.
Good flavor has not been an important part of their breeding efforts.
When it came to agricultural production, mature green tomatoes with light green shoulders were easier to spot when harvesting in the field. Wild tomatoes and many flavorful heirloom varieties typically develop dark green shoulders at maturity. Plant breeders were able to take advantage of a natural gene mutation that turns off a certain gene (SIGLK2) responsible for the increased development of chloroplasts that lead to the dark green shoulders.
Chloroplasts are the structures within plant cells where photosynthesis occurs. Tomatoes with more chloroplasts will be sweeter because they are capable of producing more sugars. Tomatoes with the turned-off gene have fewer chloroplasts, light green shoulders at maturity, and ripe fruit with less sugars.
We have been conditioned over time to think that ripe red tomatoes were the most favorable, but now gardeners and consumers are being reintroduced to the delectable rich taste of heirloom tomatoes that come in many different colors. Heirloom tomato varieties are those handed down from generation to generation because of their flavor and other desirable characteristics.
Why do some tomatoes taste so good? Desirable tomato flavor is subjective from person to person. The different components of tomato flavor are sweet, sour (acidity), salty, bitter, and savory along with various volatile compounds. The combination of the different levels of these components is what gives a particular tomato its distinctive flavor that may or may not appeal to you or me. Researchers have found that generally sweetness is the most important factor in a particular variety’s appeal.
One researcher who is working to return flavor to tomatoes is Dr. Harry Klee, a professor or horticulture at the University of Florida. He and his team at the University of Florida looked at almost 400 varieties of modern and heirloom tomatoes along with their wild tomato ancestors. They measured the chemicals associated with flavor in each variety. It is no surprise that they found modern commercial varieties contained “significantly lower amounts of many of these important flavor chemicals.”
They also mapped the genes of the tomatoes to determine the specific ones associated with each flavor chemical.
The next step is to use this knowledge to develop better tasting modern commercial tomatoes. While it would be faster to genetically engineer this change, Klee is using traditional breeding techniques because he does not want people to be afraid of eating his tomatoes.
Klee’s work has already yielded three new flavorful tomato cultivars, Garden Treasure, Garden Gem, and W Hybrid. Sound interesting? The exciting part is that he is offering gardeners seeds of each in return for a donation of $10 to his research program. If you are interested, go to his website at http://hos.ufl.edu/kleeweb/newcultivars.html.
Marianne C. Ophardt is a retired horticulturist for Washington State University Benton County Extension.