Depending on the source, the number of documented tomato varieties is anywhere from 7,500 to 10,000, with over 3,000 of those being “open pollinated”. Open pollinated simply means a tomato plant whose flowers are left to self-pollinate naturally, as opposed to being deliberately or inadvertently crossed with another variety to create a hybrid. The tomato flower of most cultivars is self pollinating. Its structure is also such that inadvertent cross pollination with another variety growing nearby is low (2-5% according to this article). Provided natural cross pollination hasn’t occurred, open pollinated varieties “breed true”, or readily produce fruits and seed with the exact same genetic material as the parent plant. All heirloom tomatoes are open pollinated, however not all open pollinated tomatoes are heirlooms.
“Heirloom” refers to thousands of varieties of tomatoes that have been carefully selected over time for color, shape, quality and taste, and genetically stabilized through generations by farmers and home gardeners. The vast genetic diversity of heirlooms finds its way into many of today’s common hybrid tomato varieties.
- “Commercial Heirlooms” are open-pollinated varieties introduced before 1940, or tomato varieties more than 50 years in circulation. These heirlooms pre-date the modern hybrid era and were typically family heirlooms that pioneering plant breeders found, improved upon and released commercially. The old Livingston varieties are perfect examples of commercial heirlooms.
- “Family Heirlooms” come from seeds that have been carefully selected for specific characteristics and genetically stabilized by individual farmers and gardeners and then passed down for several generations through a family. Family heirlooms may or may not be commercially distributed today. The U.S. is blessed with hundreds of family heirlooms due our immigrant heritage. Many newcomers to the U.S. brought their own garden seeds with them and continued to grow them here in the new world. For example Eva Purple Ball comes from the Black Forest region of Germany.
- “Created Heirlooms” start with a genetic cross of two known parents (either two heirlooms or an heirloom and a hybrid) whose successive generations of seeds have been selected, or “dehybridized,” for as many generations that it takes to achieve and stabilize the desired characteristics. This can sometimes take 10 years or more. Rosella Purple is a fine example of a created heirloom. These varieties tend to be much more recent, without the history or lore associated with the other two types of heirlooms.
So genetically speaking, heirlooms have been selected over many years for specific qualities or traits and eventually stabilized so that the seed from one year will produce the exact same plants and fruit the next year: The offspring are identical to the parents. Seeds from a hybrid variety such as Big Boy, will not breed true. Culturally speaking, heirlooms have history and lore behind them and symbolize our country’s unique melting-pot heritage. From a culinary standpoint, heirlooms offer outstanding taste, texture and versatility. They come in a beautiful array of colors, shapes and flavor profiles that form the backbone of TomatoCulture’s mission: bring our customers the best tasting tomatoes they have ever eaten, whether fresh, dried, preserved or fashioned into delicious products.