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Hand-pollinating takes
dedication
Why would a home gardener want to hybridize
her own plants? "The joy of painting with DNA," says Alice
Doyle, co-owner of Log House Plants. Less poetic but more to the
point, Duncan McGlashan, a British amateur delphinium breeder,
says it's the joy of developing something all your own. "It
really is very satisfying thinking what you've got is original.
That's the appeal."
Breeding delphiniums takes patience and persistence. Here's what
you need to know to give it a try:
- First a little botany lesson: The delphinium plant reproduces
when pollen from the anther (the male reproductive part) is
transferred to the stigma (the female reproduction part) and
moves down the style to the ovaries, where
fertilization takes place and seeds develop. You'll be
able to tell the anther from the stigma because the anthers will
be covered with fuzzy yellow pollen. Both occur on the same
plant.
- Start with two named varieties (parents) from a nursery and
label them.
- Decide which will give pollen and which will receive (mother
plant). When plants begin to bloom in June or July, begin
stripping anthers off the mother plant (so that it doesn't
pollinate itself). The florets open from the bottom of the stalk
up, so work from the bottom up until all florets have opened and
you've removed all anthers. Don't get behind on this
process because the stigma become receptive early on and you
don't want the plant to pollinate itself. Once the plant starts
to bloom, the process of hand-pollinating can take up to three
weeks.
- Stigmas are ready to receive pollen when the tubes of the
stigma swell slightly like an umbrella and get a little sticky
in order to attract the pollen. When you think stigmas are
almost ready, pick the florets from the other parent plant (the
ones with anthers), put them in a box and move indoors for a day
or two to dry. When stigmas are ready, brush pollen from anthers
onto the stigmas. Either pull back the petals from around the
anther and dab pollen onto the stigma, or use a small brush to
transfer pollen.
- It's a tedious task, but in order to get a pure new variety,
you need to pollinate all the florets on a spike. To be sure
you've pollinated when the stigma is receptive, you can brush on
pollen more than once. McGlashan usually
does it three to four times.
- If you're working with more than one pair of parents, wash
your hands before you move to a different plant or you may mix
pollen and your cross won't be pure.
- It takes about three weeks to get ripe seed. Once seed is
ripe, collect it and germinate right away or store in
refrigerator in paper or glassine bags inside a closed jar. When
ready to germinate, put jar of seed in freezer for five days.
Then sprinkle into sterile planting mix and cover lightly. Put
container into a bigger container that holds water so moisture
can wick up. Spray top of soil with water. Keep in dark and they
should germinate in about 10 days. Once they come up, move into
the light.
- The next year when your new plants bloom, choose the one you
like the best. Cross that with a named plant that has the
characteristic you want. Sooner or later, you're sure to get
something wonderful.
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