In a continuing effort to develop tastier tomatoes, a group of U.S. Department of Researchers has put 173 varieties to the test.

The goal was to identify the ones that offered the greatest potential for boosting flavor among commercial varieties and breeding lines, according to a news release.

Agricultural Research Service molecular biologist Joanne Labate and plant geneticist Larry Robertson, both of Geneva, N.Y., worked with Dilip Panthee, an assistant horticulture professor at with North Carolina State University, Fletcher.

They planted the 173 varieties in test plots in North Carolina and trained 10 volunteers in sensory analysis.

The varieties were selected from about 6,000 accessions in the Agricultural Research Service's Tomato Germplasm Collection in Geneva.

The volunteers were asked to rate the varieties on a scale of 1 to 5 in four sensory areas: odor, taste, flavor and texture.

Although hundreds of compounds go into flavor other other characteristics, two play a key role: sugar and acid.

Although the amount of acid varied only slightly between all varieties, there was a wide variety in sugar content.

There's also a positive correlation between sweetness and flavor—the sweeter the tomato, the more flavor it contained.

Because both characteristics can be easily measured, breeding to enhance flavor shouldn't be that difficult, according to the release.