Marisa Thompson, Southwest Yard and Garden Published 3:12 a.m. MT April 12, 2020

Small fruit are developing at the base of the female flower (bottom left), but not on the male flower (top left). Pollen from the stamens in the center of the open male flower (top right) can be translocated to the stigma in the center of the open female flower (bottom right) by pollinating insects or by humans.(Photo: Abrahami, Wikimedia Commons)

Question: I would love to be able to grow both zucchini and watermelon this year, but I am hesitant because of problems with cross-pollination in the past. Any tips?

Seed to Supper online course participant, somewhere in New Mexico

Answer: First of all, for readers who dont already know about New Mexico State University'sSeed to Supper program through ICAN (Ideas for Cooking & Nutrition), this is a free, online, self-paced beginning gardening course that was first developed by the Oregon State University Extension Service and modified by our own NMSU Food Systems Specialist Sally Cassady to be web-based and New Mexico-oriented (https://ican.nmsu.edu/seedtosupper.html).

It sounds like the problems youve had in the past with zucchinis and watermelons may have been more about fruit set issues which could include pollination problems than cross-pollination. Cross-pollination can only occur within plants of the same species. The old gardening tip dont plant cucumbers next to squash or melons because theyll cross-pollinate and form bad fruit isnt true. NMSU Extension Vegetable Specialist Stephanie Walker confirmed: As long as the cucurbits are different species, its very unlikely theyll cross-pollinate. Zucchini is Cucurbita pepo and watermelons are Citrullus lanatus, so they wont cross-pollinate to produce viable seed.

Marisa Y. Thompson(Photo: Courtesy)

Plants in the cucurbit (gourd) family include melons, pumpkins, squashand cucumbers. Each of those different cucurbits includes plants of different species and genera (plural of genus). Remember, the scientific names of plants consist of two parts: the genus and the species. So musk melons scientific or botanical name is Cucumis melo, with Cucumis as the genus and melo as the species. Cucumber is Cucumis sativus, so even though musk melons and cucumbers are in the same genus (Cucumis), they are not the same species and wont be likely to cross-pollinate. Even if they did cross-pollinate, the evidence would not be visible in this years crop. If you saved seed from cross-pollinated fruit and grew it next year, you might get something cool and yummy, although its more likely to be undesirable. Pumpkins with green bumps could be the result of seeds that were saved from normal pumpkins crossed with green-warted gourds.

Its not just that plants from different species arent likely to cross-pollinate based on their genetics. Amanda Skidmore, NMSU Extension integrated pest management specialist for urban and small farms, explains that our pollinators are picky too: Interestingly, different pollinators will visit each plant because of the flower shape and inflorescence. For example, squash bees will visit zucchini, but not watermelon.Skidmore encourages gardeners to take some time to watch and see what different pollinators are visiting the two plants. There will be some overlap (honey bees, bumble bees), but some cool differences too.

For information, check out our NMSU Extension Guide collection for vegetables. Related titles include Starting Plants Early Outdoors, Spices and Herbs for the Home Garden, Home Vegetable Gardening in New Mexico and Growing Zones, Recommended Crop Varieties, and Planting and Harvesting Information for Home Vegetable Gardens in New Mexico.

As retired NMSU Extension Horticulture Specialist Curtis Smith explained in a 2008 column, cucurbits have separate male and female flowers on the same plant. You can recognize the male flowers because they do not have a small fruit behind them (more on this later). They produce the pollen needed to form the fruit, but they do not produce the fruit. The female flower, on the other hand, has a small fruit behind the flower even before it opens. The female flower cannot produce the pollen needed to cause the fruit to develop and is dependent upon insect (or human) pollinators to transport the pollen from the male flower. The male flowers begin forming before the female flowers form. So, it is possible to have cucurbits blooming, but not producing fruit. The time between the first development of male flowers and the female flowers depends on plant variety and environmental conditions. Your problem may just be that the female blossoms have not formed yet. They should be forming soon. However, if you see the female flowers on your cucurbit plants, but they are not "setting" fruit, then the problem may be that you do not have pollinators.

Smith also offers tips on how to pollinate your cucurbit flowers yourself: Each morning, collect pollen from the stamens in the center of the male flowers and then transfer that pollen to the stigma in the center of the female flowers. Use a small, soft-bristled paintbrush to do this. If you are successful, you should see small fruit forming within a few days. Leave some female flowers unpollinated (by you), so you can watch for the return of the natural pollinators to relieve you of the early morning effort of pollination.

A few years ago, I wasnt convinced that Id be able to tell the difference between male and female flowers on a squash plant. That is, until I looked closer. Both flower types are huge and bright orange-yellow, but if you look just behind the flowers, youll know when you find a female versus a male because theres a swollen fruit structure developing at the base of female flowers. In some cucurbits, that baby fruit will be more rounded, and in others more like a small pickle.

For gardening information, including decades of archived Southwest Yard & Garden columns, visit the NMSU Extension Horticulture page (http://desertblooms.nmsu.edu/), follow us on social media (@NMDesertBlooms), or contact your County Extension office (https://aces.nmsu.edu/county).

Marisa Thompson, PhD, is the Extension Horticulture Specialist for New Mexico State University and is based at the Agricultural Science Center at Los Lunas.

More Southwest Yard and Garden:

Read or Share this story: https://www.lcsun-news.com/story/life/2020/04/12/exploring-gourd-family-cucumbers-squashes-and-melons/5126335002/

See original here:
Exploring the gourd family of cucumbers, squashes and melons - Las Cruces Sun-News

Comments are closed.