1 - Science says that it is very unlilely for melons and cucumbers to hybridize, but maybe not impossible.
Q. I am an amateur gardener in Albuquerque and have been growing various herbs, tomatoes and vegetables for the last fifteen years. Today I noticed a green (1-2lb) fruit mixed in with my trellised melons. I picked it, cut it and tasted it. It seemed to be a melon-cucumber cross. The fruit is supple (ripe); the taste is mostly cucumber with a slight sweet taste. The seed pocket was more like a melon; I scooped it easily with a spoon. It is growing in my melon patch, not my cucumber patch. I have one more fruit on this vine. It appears on a vine that is healthy instead of waning like the rest and it seems as though the fruit grew very quickly like a cucumber. I have read that in general, the two are of different species and will not cross. I beg to differ. Perhaps there is a closer relationship between the varieties I have grown over the years, less of a distinction between species. It is actually very tasty, and I'd like to save the seeds.
A. I talked to Dr. Chris Cramer, NMSU's Onion Breeder who has also bred cucumbers. He agreed that melons and cucumbers should not hybridize since they are in different plant species. He pointed out that the species containing the melons (Cucumis melo) is a very large and diverse group of plants, so it is possible to have a plant that is a melon with a green rind and white flesh like yours. The most probable answer is that you may have had an off-type seed in your seed packet. Seed companies clean their equipment between varieties of vegetables, but it is possible that one or a few seeds of a previously cleaned variety remained in the machinery and wound up in your packet. Dr. Cramer also suggested that it was possible two different melons crossed in the seed production field, producing one that was atypical for the variety that you planted. Either of these is the most accurate way to explain what happened to produce the interesting fruit in your garden. That is the scientific answer, but sometimes things happen that are not supposed to happen. So, although it is very unlikely for a cucumber (Cucumis sativus) to hybridize with a melon (Cucumis melo), it is not totally impossible. If you want to test the hypothesis that this happened in your garden, you can try growing them and observing the characteristics of the fruit produced for several generations (several years) in your garden. This can be an interesting process, but will require that you take measures to prevent cross-pollination with other melons (and cucumbers) in your garden as you do this. You can grow your test plants in a screen cage to keep natural pollinators out. An easier option is to hand-pollinate the flowers (pollen from male flowers of one plant from your saved seed to a female flower on a different plant from the same group of seeds) and place a mesh bag around the hand-pollinated flower until the fruit begins to develop. Mark the hand-pollinated fruit to distinguish them from fruit that may have formed from pollen brought by natural pollinators. Save seed only from the hand-pollinated fruit for the next year. By doing this, you will not allow foreign pollen to affect the plant. If it is a hybrid plant (from hybridization in your garden, or at the seed producer's field) the characteristics of the original parents will become apparent in the offspring. If you are correct, after a few years, some plants will produce cucumber-like fruit while others produce melon-like fruit. There may be a number of things in between. If this plant was just a type of melon, then the offspring's fruits will be melon-like. A final consideration is that there is a plant called Armenian cucumber that is actually a melon (Cucumis melo), but because of its long narrow shape and flavor, is eaten as a slicing (salad) cucumber. This melon has a greater chance of hybridizing with other melons.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: email@example.com, office: 505-865-7340, ext. 113.
For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.
Please copy your County Extension Agent and indicate your county of residence when you submit your question!