Just wanted to explore some of the statements in this paragraph;
Lycopersicon lycopersicum
Almost all modern tomatoes can be safely grown without isolation and will not cross—'currant' tomatoes (such as Cherry Tomatoes), and 'potato-leafed' tomatoes (such as Brandywine) are possible exceptions and may cross other currant or potato-leaf varieties. Grow as many standard tomatoes as desired, but grow only one currant tomato or one potato-leaf tomato at a time to ensure purity (or cage them, or separate varieties by 500 feet). Currant and potato-leaf tomatoes will not usually cross with common tomato varieties.
It's best to not plant all a valuable variety's seeds in one season until you are sure it doesn't cross with any other varieties you grow.
I think very high percentage gardeners who grow tomatoes don't bag blossoms or isolate their plants.Why do they fail to do this?Because "Almost all modern tomatoes can be safely grown without isolation and will not cross."I think the number ranges from 95 to 100 percent.
And it is has been proven that potato leaf varieties cross more readily than regular leaf varieties. I cannot remember the exact figure but the picture in my mind is 60s or 80 percent something purity.
As far as the currant tomatoes I have no idea.Jeffrey H. McCormack explains why potato leaf and some other tomato varieties cross more readily in this excellent report.
http://www.michiganheirlooms.com/PDF...Production.pdf
Generally speaking, most modern varieties (introduced after 1950) can be isolated from each other
by a relatively short distance. This is because most modern tomato varieties have a blossom structure
in which the length of style does not exceed the length of the anther cone. This arrangement of flower
structure favors self-fertilization. Older tomato varieties, potato-leaf varieties, and large-fruited,4
beefsteak-type tomatoes (including varieties with double blossoms) tend to have an “exserted style,”
meaning that the style protrudes beyond the anther cone, typically by a millimeter or more. This
arrangement of reproductive parts favors cross-fertilization by pollinating wild bees. Some garden
tomatoes have retained some of the characteristics of their wild ancestors. These characteristics may
be found in many cherry tomatoes and currant tomatoes. These types have a blossom structure such
that the style protrudes considerably beyond the anther cone
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