Researchers at Cold Spring Harbor Laboratory say their new genetic toolkit to improve tomato yield without compromising flavor can be used in all varieties, from plum to cherry. Courtesy of Zach Lippman/Cold Spring Harbor Laboratory hide caption

itoggle caption Courtesy of Zach Lippman/Cold Spring Harbor Laboratory

Ammunition in the form of tomatoes are thrown to a crowd gathered for the annual Tomatina Festival in Bunol, Spain, near Valencia, Wednesday. AFP/AFP/Getty Images hide caption

itoggle caption AFP/AFP/Getty Images

A Cherokee purple tomato grown in Alaska in 2011. Sherry Shiesl/Tatiana's TOMATObase hide caption

itoggle caption Sherry Shiesl/Tatiana's TOMATObase

The taste of Mock's tomatoes starts with the seed. He uses only organic varieties, including cherry and several heirloom varieties. Allison Aubrey/NPR hide caption

itoggle caption Allison Aubrey/NPR

A worker separates tomatoes at a market in Mexico City. The Commerce Department says it might act to end a 16-year-old trade deal governing fresh Mexican tomatoes sold in the U.S. Gregory Bull/AP hide caption

itoggle caption Gregory Bull/AP

Notice how some of these tomatoes have unripe-looking tops? Those "green shoulders" are actually the keys to flavor. pocius/Flickr.com hide caption

itoggle caption pocius/Flickr.com

A tomato expert recommends planting seedlings in rich soil with lots of organic matter and a steady slow-release fertilizer. iStockphoto.com hide caption

itoggle caption iStockphoto.com