Cross-Pollination:
What it is and how to Prevent it
How to know what garden plants will cross with other garden plants
The goal of seed saving is to get true-to-type seeds. If you’re going to the trouble of saving seeds, you certainly don’t want to plant those seeds and then grow some frankin’ thing that may be inedible!
But never fear! There is a simple way to know what plants will cross-pollinate with other plants.
The Following is true for Vegetables and Flowers.
In order to determine if a vegetable plant or flower will cross with another plant, one needs to know the scientific name. This name can be found for each of the plants at the Jefferson Seed Library on the growing tips and catalog pages.
The scientific name is composed of the Genius and species. The Genius will be capitalized and the species will be lower case. Both will be in italics. There are also different varieties with in the species. So, knowing the scientific name for the variety is crucial to knowing if it will cross with another variety.
The A, B, C’s
of how it works…
A. If the Genius is the same but the species are different, the plants will NOT cross.
B. If the Genius and the species are the same, the plants WILL cross.
C. If the Genius is different, the plants will NOT cross.
Example:
Say you have 3 varieties of pumpkins:
• Halloween
• Big
• Kabocha
First, find the scientific name. (A google search will usually give the correct scientific name, but not always. Check the seed catalog and/or the reference section at JPL for books which contain the scientific name for accurate information.)
All three pumpkins are Genius Cucurbita.
- Cucurbita pepo Halloween
- Cucurbita maxima Big
- Cucurbita maxima Kabocha
Second, see what names match. For all three varieties the Genius is Cucurbita. But only the varieties, Big and Kabocha are the same species, maxima.
Third, follow the A, B, C’s.
A. If the Genius is the same but the species are different, the plants will NOT cross.
The Genius, Cucurbita, is the same for all three, but Halloween is a different species than Big or Kabocha. Therefore, Halloween (pepo) will NOT cross with Big or Kabocha (maxima).
B. If the Genius and the species are the same, the plants WILL cross.
Since Big and Kabocha are the same species, maxima, they WILL cross. This means if isolation guidelines are not followed, you will get frankin squash if you grow both and save their seeds! You can find the isolation guidelines on the growing tips page.
Interesting fact:
Cucurbita is a member of the gourd family. Its members include Zucchini and other squashes, some gourds, and (of course) pumpkins. There are also many more species than were discussed here.
For a more in-depth explanation of cross-pollination visit Walter Reeves, Georgia Gardener.