Tim Baker, Extension Professional and Horticulture Specialist
Occasionally a vegetable gardener will ask me if closely related plants will cross and affect the flavor of the vegetables they are growing in their garden. Usually this is not a problem, unless you are saving seed.
Normally even if two plants will cross, the flavor of the vegetable in question will remain the same as its parent for the summer that you planted it. If you save seed, however, the flavor of future crops may change, if new genetics have been introduced through cross-pollination.
Some exceptions do exist. One example is corn, where pollen from another type of corn can affect the type you are growing. Plant breeders refer to this trait as xenia. An example of this is where pollen from field corn affects the sweet corn you are growing and produces starchy kernels instead of sugary ones.
The Cucurbitaceae (melons, pumpkins, squash, and gourds) usually do not have this problem. Some of them will not cross naturally anyway. But seed savers have to know what they are doing and insure that possible crosses are guarded against.
Still, rumors about same-year flavor changes in the plant you are growing persist. One, for example, holds that cucumbers will cross with cantaloupes and ruin their flavor. These plants are both in the same genus (Cucumis), but belong to different species. Normally, these will not cross, and even if they did, it is doubtful that the flavor would be affected in that current year.
Poor flavor in cantaloupes could be due to either genetics or environment. If your cantaloupes have a problem with flavor, try changing varieties, or look for some cultural or environmental factor that is causing the problem.
Watermelons do not cross with other vine crops, except for citron, which is closely related. Since most gardeners don’t grow citrons, that’s usually not a concern.
Pumpkin, squash and gourds present another problem, which can be complex. Some will cross, while others will not. Again, I would not be too concerned about it, unless you are saving seed. If you are doing that, you should get a good book on the subject and learn what to do.
The reason that pumpkins, squash and gourds present a complex situation is that the common classifications do not follow the botanical divisions between species. In other words, what we commonly call pumpkins may occur in several species.
In summary, except for corn, don’t worry about cross-pollination affecting the flavor of this year’s crop. However, if you are saving seed, it is best to get a good book on the topic and follow the rules closely.
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