Question: I have numerous tomato seedlings that volunteer-sprout in my vegetable beds each year. I typically pull them up, but it occurred to me that I may have some new tomato cultivar. Last year, I planted eight types, mostly heirloom. It’s possible that cross-pollination could lead to some of these being hybrids, right?
Answer: Gardeners are often curious enough to let self-sown vegetable seedlings continue growing in their garden or compost pile. It’s possible that these volunteers are a product of cross-pollination, but the chances vary from species to species. Tomatoes are primarily a self-pollinating species due to their relatively closed floral structure, although the openness of a tomato plant’s flowers can differ from cultivar to cultivar. Therefore, it’s most likely that your volunteers, which are all the product of open-pollinated heirlooms that grow true to type, will resemble their parent.
To be extra careful, seed savers typically isolate tomato cultivars from one another to ensure that the seeds they collect are true to type, keeping cultivars 10 to 50 feet apart. However, even without such a distance, it’s likely that the fruit is the product of self-pollination. Chances of cross-pollination are usually estimated as being below 5 percent for most tomato cultivars. This low rate of cross-pollination is why primarily self-pollinating or “autogamous” crops, such as tomatoes, peas, lettuces, and most beans, are ideal for novice seed savers.
If you’d included an F1 hybrid in your garden, rather than all heirlooms, the resulting seeds would be more varied because F1 hybrids don’t produce seed that’s true to type — even if the plant is self-pollinated. The hybrid seeds would bear traits that were more likely to vary genetically because the parents of hybrids are wildly different from one another. - Lee Buttala, Seed-Saving Expert
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