Freezing pollen tutorial

[Wires_Guy_wires]

Hi all,

I've been freezing pollen and using them succesfully for about 10 years now. Efficiency lowers a lot when storing pollen, but a year or two in the freezer should at least yield you a couple seeds.
I saw today that my arakawa maple is flowering, I might want to hybridize it with trident in a couole years.

Here's my protocol:
1. Get eppendorf tubes (1.5mL or smaller PCR strips). Get dry rice and regular ground flour (the cheapest).
2. Wait for the plant to flower, put it in a dry location when flowering starts.
3. Use a toothpick or tweezer to collect pollen or pollen structures like anthers, put those in the tube and add rice.
4. Let it dry overnight and carefully remove all rice kernels except the bottom three.
5. Shake the devil out of it. You want all the pollen to release.
6. Carefully remove all large plant matter. Keep the rice. And the pollen of course, keep that too.
7. Estimate the amount of pollen you have and add 3-4x as much dry flour. Shake the devil out of it again.
8. Divide the flour-pollen mixture over multiple tubes. This way you can do multiple pollinations without having to thaw your stock.
9. Freeze at -20°C. Keep frozen until use!
10. When the time of use has come, follow these rules: always, always work in dry conditions. Don't wear static clothing. Always, always let the pollen tube thaw to room temperature for at least 30!! Minutes. Use directly after that. In dry conditions. Is it raining? That's not dry.. I use a tiny soft paint brush to paint the pollen-flour mixture on the flowers, and I use some water and detergent on the brush when I'm done to prevent cross pollination. I let the brush dry on the heater. Toothpicks might work too, cotton swabs don't.

Repeat the painting daily during the flowering period, once thawed it should be good to use for two to six days. Not all flowers are receptive at the same time, and it can take some time to figure out their peak moment. So do it often, better one time too many than too few.

Has worked on tropicals, sarracenia, orchids, cannabis and cherries.. Thus far.
Efficiency is low, but the effort and costs are too.
Does it work all the time? No. Probably not. But I'm reliably getting results, not great results, but 3-40% of the pollinated flowers producing seeds is pretty much more than 0.

Funny pro tip: some plants release their pollen more easily when there are vibrations involved. If you have an electric toothbrush or erhmm.. something else.. It can help you shake the pollen from the flowers. Bumblebees and other bees are known to use this strategy. Videos on youtube of them shaking their bum!
Another tip: Air contains water and water is no bueno for pollen (see the part about dry) so the less air there is in the plastic tube, the better the preservation. If you have just a lil bit of pollen, consider using a smaller tube.


Have fun!

 

[Bonsai Nut]

I am going to move this to the advanced subjects forum. I was thinking about this the other day and its application for princess persimmons and winterberries.

 

[Wires_Guy_wires]

Cool, no problem!
Here's an explanatory video on vibrations. Apparently it's called buzz pollination.

It works even if the plants have no hidden pollen, to shake the pollen off of the anthers and helps breaking up large clumps that will act as a water attracting structure.
The finer the dust, the better your chances. But I do not recommend using ultrasonic vibrations as these will damage the cell structure.

 

[Shibui]

Do you bother covering your hand pollinated flowers?
Subsequent pollen from wind or visiting bees could override your cross.
My sources say that many flowers have mechanisms to favour growth of pollen from the same species and slow growth of different pollen which reduces natural hybridization. Making sure that no other pollen gets onto the stigmas is one way to enhance success of hybridizing trials.

 

[R0b]

I like your solution of using rice to dry the pollen.

Do you expect interspecific crosses to work in maple?

 

[Rivian]

I like your solution of using rice to dry the pollen.

Do you expect interspecific crosses to work in maple?

Interspecific crosses in genus Acer are well documented.
Esveld even offers one intersubgeneric cross.
As buergerianum x palmatum would be.

 

[Wires_Guy_wires]

Do you bother covering your hand pollinated flowers?
Subsequent pollen from wind or visiting bees could override your cross.
My sources say that many flowers have mechanisms to favour growth of pollen from the same species and slow growth of different pollen which reduces natural hybridization. Making sure that no other pollen gets onto the stigmas is one way to enhance success of hybridizing trials.

It depends on the type of flower, with actual flowers I bag the flower sometimes with a nylon fabric bag. But it comes with the risk that it's a wind catcher.
Some flowers are so early that there are very little pollinators out there so I don't bag.
When the plants are indoors, I don't bag either.

In cannabis and in the future, pines too, I wouldn't bother covering them. They're wind pollinators, so mesh bags wouldn't make sense as the wildtype pollen blow straight through it, and since my mesh is nylon, if they become static they might attract more pollen even.
This does mean that there is a possibility of a mixed batch of offspring.

I've read stories of people cutting down the stigmas to stubs, then pollinate. The pollen tube should still grow if pollen comes into contact with the stigma stub, but it reduces the chances of bees hitting the right spot.
Another strategy can be to remove petals, so that the flower is no longer attractive.
One other strategy is to remove the anthers as well, making the flower even less attractive.
Most pollinators work with visual cues, so if those cues are gone they're unlikely to visit the flower.