Gardening Articles: Care :: Plant Care Techniques

Breeding Your Own Squash (page 4 of 6)

by Carol Deppe

How to Hand-Pollinate

Squash and pumpkin plants have separate male and female flowers on the same plant. The female flower buds have a baby squash at the base; the male flower buds don't. The baby squash reflects the shape, and sometimes the color of squash that the plant will produce.

Tape-ready buds have a yellowish color lacking in younger buds and often gape at the tip. Locate buds that are at the right stage, and tape the chosen male and female flower buds shut late in the afternoon or evening before they are due to open for the first time. This is necessary to exclude pollinating insects, which are unlikely to consult you about the kind of pollen you want on each flower. Don't tape the buds any earlier, because they grow quite a bit in that last day, and they would rip open as they grow against the restricting tape.

Plants usually produce several male buds early in the flowering season, before they produce any female buds. Don't get discouraged if you can't tell whether buds are male or female when the plants have just started flowering; there probably aren't any female buds yet. Keep watching.

Next, mark the positions of the taped buds to find them quickly the next morning. I use bamboo stakes with tags of colorful surveyor's tape. (Use different colors of tape to mark male and female buds.)

Hand pollinations are most likely to succeed when they are done on one of the first few female flower buds the plant produces. In addition, fruits often drop off early in development if an earlier fruit is growing on the same vine. So, to maximize the success rate for hand pollinations, do them early in the flowering season. If a fruit has already set on the vine before you hand-pollinate, remove it to eliminate the competition. I usually do at least six hand pollinations (using different plants or combinations of plants) for each variety I want to save seed from.

My success rate with this method is better than 90 percent. Nearly every cross succeeds. My success rate on somewhat later flower buds, and with no removal of competing fruits, is only about 20 percent.

The right time for hand pollination is in the morning, as soon as possible after the male flowers release their pollen (so that it is soft and loose and fluffy, and ready to come off the anthers at the slightest touch, not moist and sticking tightly to the anthers). The exact timing varies with weather conditions, being later if the morning is colder or the plants are wetter. In most areas, 7 to 11AM is the useful period. You can examine untaped flowers to see whether they have released their pollen yet.

When you're ready to pollinate, pick the taped male bud, and carefully tear the petals off, exposing the pollen-bearing anther. Tear off the taped end of the female bud, and daub the pollen onto the stigma, using the stripped male flower as a pollen-transfer stick.

If many bees are active in your squash or pumpkin patch, watch them and work quickly once the buds are exposed. Sometimes, bumblebees will dive into a bud you're holding and rip off all the pollen right before your eyes.

Use all the pollen from one male bud to pollinate just one female flower. (Various books claim that you can use pollen from a male bud to cover two or three female buds, but I've found that this lowers the success rate dramatically.) Finish pollinations by late morning. Later hand pollinations are less likely to succeed. Also, by late morning, the pollen has dropped off the anthers inside the male flower buds and is trapped in and stuck to the base of the petals, where it is much more difficult to recover and work with.

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