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Filial Generations


Naming Conventions


By: “Doctor Sine” aka Randy Sine


Mariseeds arguably offers the widest selection of heirloom tomato seeds available anywhere.  Additionally, Mariseeds has assembled some of the best breeders in America to create the innovative concept of “Create Your Own Heirlooms”.  In perusing the breeders pages you’ll notice the variety names are followed by an F, which stands for filial, and a number (e.g. F4).  This designation denotes the generation or generations after the parental generation.  When two parents are cross pollinated the seeds saved from the resulting fruit contain F1 seeds.  When those seeds are sown and the F1 plants are grown out the resulting saved seeds are F2.  The next generation is F3 and so on.  The lower the filial generation number the more variations there are.  So, people who like surprises should focus on the lower filial generations.  The higher the filial generation number the more stable they are and people wanting something that is likely to be close to the variety description should focus on those.  Also note that when the two parents are stable (aka open pollinated) all resulting F1 plants should be the same.  Commercial F1 hybrids are created to obtain the desirable characteristics in the F1 plants and fruit.  On the other hand Mariseed breeders are more interested in pursuing characteristics in F2 and beyond with an eye towards stability.  Once stable the variety is then considered open pollinated.  After several years the variety can then be referred to as an heirloom.


In cases where a grow out is done and the results don’t match the variety description, but is desirable in some way it can be named whatever you want and you’re welcome to save seeds and grow it out until stable.  This is the principle behind “Create Your Own Heirloom”.  On the other hand if a grow out is done and the resulting plant and fruit matches the variety description then you should name it as your strain if you plan to save seeds and pursue stabilizing it yourself.  This is because unless the breeder is present to witness all aspects of the plant, production, fruit and flavor there could be subtle differences.  In this case use the convention for naming strains.  I’ll use Brandywine as an example because it has several recognized strains.  Many heirloom growers are familiar with the Sudduth strain of Brandywine.  It is often listed as Brandywine Sudduth’s Strain or Brandywine, Sudduth and sometimes Brandywine (Sudduth).  Of those forms the latter two are considered more correct.   Therefore if you grow out a variety called Pinky that is a Potato Leaf plant with pink fruit and a pointy end you would name it Pinky, “strain name”.  “Strain name” can be anything you want, but the most commonly accepted practice is to use your first or last name.  This will avoid the future confusion of having two varieties of the same name with slightly different characteristics.