Cross Pollination

[Caesar]

Hey guys! I'm making this thread, hoping that it will act as a centralized hub for queries on cross pollination (not sure if there already is one, let me know if there is). The thread can be used for generalized questions as well as species-specific queries (like mine), and I hope any further questions on the subject will be placed here.


So, first question(s)... 1) How do I emasculate Rubus flowers? I have the tropical R. rosifolius flowering right now, as well as the temperate R. idaeus 'Caroline'. Do I have to open up the closed flowers to reach the anthers, or is there a window of opportunity when recently opened where the pollen is still immature? ; 2) How do I actually execute the pollination? When to harvest the pollen?, how to harvest it?, when to apply it?, for how long is it viable?... I assume I'll need a little brush, but the prior matters elude me. ; 3) How do I isolate the flowers? A little bag? If so, what kind? And for how long do I need to isolate them?

[Caesar]

Anyone? I have a small window of opportunity with the blossoms, and I wanna get my plant-breeding freak on. 

[simon_grow]

I've never hand pollinated Rubus before but here is what I would do based on my knowledge of plants:

Wait until your rubus flowers are almost fully formed but the petals are still closed. Remove all anthers leaving the petal. Take a look at the pollen sacks under a microscope or using magnifying glass to ensure pollen was not released yet. Bag the emasculated flower. Collect ripe pollen and pollinate bagged flower, I'm guessing the next day. Make sure you tag each flower. You may want to try pollinating the flowers at 12 hours and 48 hours after emasculation to ensure proper pollination.


See 29 minutes into the video. https://m.youtube.com/watch?v=u5Wn8HIlb6I

Simon

[Caesar]

Thanks for the advice! It was much appreciated, and the video helped a lot. 

[simon_grow]

Your welcome, I miss typed earlier. I meant to say " remove all anthers leaving the Pistil". The top of the pistil also known as the stigma is where you want to put the pollen. Good luck,

Simon

[Solko]

Hi Caesar,

Nice thread and subject. Here is an excellent high definition and high-quality video on the subject that should answer all your questions:

https://www.youtube.com/watch?v=_i2_soyLDSQ&index=3&list=PL60FnyEY-eJAMOPvU-yyF4JfuW5ocJvC4

It is on apples, but you should be able to make a good estimate or guess on how it works for Rubus. I don't know much about that genus, but because most of these things are so general for most plants, I would guess that:

1) yes, you should emasculate the flowers you want to pollinate (the females) by opening them the day before they open and snipping of the anthers before they ripen (with a small pair of clippers or scissors) - I wouldn't risk waiting until they open.
2) Harvest the pollen sacks from the plant you want to be the father (the males) in a little container and let them ripen and dry at room temperature for a day or two - then you can pollinate the emasculated female flowers with a little brush (or your finger)
3) It could be wise to put a little bag over the flowers, or the entire branch with flowers you cross pollinated. Isolate them until all other flowers are gone.


But again, all details and much more info is in the video. Get that breeding freak on! 

Good luck!

[Caesar]

Hi Caesar,

Nice thread and subject. Here is an excellent high definition and high-quality video on the subject that should answer all your questions:

https://www.youtube.com/watch?v=_i2_soyLDSQ&index=3&list=PL60FnyEY-eJAMOPvU-yyF4JfuW5ocJvC4

It is on apples, but you should be able to make a good estimate or guess on how it works for Rubus. I don't know much about that genus, but because most of these things are so general for most plants, I would guess that:

1) yes, you should emasculate the flowers you want to pollinate (the females) by opening them the day before they open and snipping of the anthers before they ripen (with a small pair of clippers or scissors) - I wouldn't risk waiting until they open.
2) Harvest the pollen sacks from the plant you want to be the father (the males) in a little container and let them ripen and dry at room temperature for a day or two - then you can pollinate the emasculated female flowers with a little brush (or your finger)
3) It could be wise to put a little bag over the flowers, or the entire branch with flowers you cross pollinated. Isolate them until all other flowers are gone.


But again, all details and much more info is in the video. Get that breeding freak on! 

Good luck!

Wow! Great video! And really helpful advice. It all really helped me visualize how to carry it out. Unfortunately, I may be a little too late for this crop. I checked yesterday morning, and most of the flowers were already open. And I'm still lacking a few resources (I'm hoping to acquire them today). If I can get the materials here before the last blossom opens, I might be able to do it, but I'm not counting on it. I probably should've prepared before hand (especially since this was a planned cross), but the bloom caught me completely by surprise. Nevertheless, now that I know the parent species will flower in my climate, I'm definitely gonna carry out this cross on the next bloom. It's not just a hobby, I've got my university in on it too. 

I don't think I'll give a play-by-play just yet, but I'll be recording the whole process. If successful, I'll definitely be posting the full project here. For now, I supposed I'll just enjoy these as a small crop of raspberries. One more question, though: does the pollen 'have' to be in the balloon stage, or can I harvest pollen from a fully opened flower of the male parent?

[Solko]

That is a good question, I never bother to isolate he pollen-donating flowers, especially for experiments. I just collect pollen from open flowers.
I guess some people want to make 100 percent sure and exclude the remote possibility to get a few grains of pollen from another plant, deposited by insects on the flower that you want to take the pollen from.
But I usually don't bother, especially when you make a cross of two different species. The progeny of successful crosses will probably look so different from a 'non-cross-pollination', that even if there are a few 'pure' seedlings, it will be easy to seperate those out.
The female flowers are the really important ones to get before they open.

[Caesar]

I don't think I'll have to worry about stray pollen grains under my circumstances, but I managed to collect pollen from open flowers on both parents today, to try the hybrid both ways. I'm letting it dry, and I think I'll try something out on sunday. Caroline was meant to be the seed parent, but if it stops blooming before I'm ready, I'll store away the pollen, and try Caroline's pollen on the other flower. Hopefully, I'll get good results either way, but the whole "cracking open an immature-pollen flower" successfully is the part that worries me.

[Caesar]

I've been carefully documenting the breeding progress in words and photos, and it seems that both of my flowers have been successfully cross-pollinated! I'm so excited, I feel like a little kid! But I shouldn't celebrate just yet. The fruit has to mature first, and a lot could go wrong before and after that point. Which brings me to my next (non-pollination-related) question: How do you germinate bramble seeds? I've tried R. parvifolius, R. niveus, and an un-named Blackberry, and so far none have grown, even when stratified (though I didn't stratify Rn 'cause it was tropical).

[Solko]

Congratulations Caesar, that sounds good! I have no experience with germination of Rubus sp. but since it is mostly temperate, I would wash the seeds, dry them for a couple of days. Then soak them for day to rehydrate them again, put them in a plastic bag with some moist perlite or vermiculite in the fridge for 6 weeks and after that put them in a warm place. This is just my standard germination procedure for temperate small seeds. It is possible they need longer stratification, or don't need it at all. You could ask Marcus from Gardenvideo.com He does a lot of breeding work with Rubus spp. I am sure he is very busy, but he seems helpful, so it would be worth it to ask him.

https://www.youtube.com/watch?v=4jlObrsl5nY

[Caesar]

The advice and the contact was much appreciated, thank you! Seems better than the other technique I read, where you just slip the dry seeds in a fridge for a month or three. Moist stratification is probably how it happens most often in nature anyway. I just wasn't too sure about the specifics.

As for the experiment, dead end. The fruits didn't develop on R. idaeus (should've been more diligent pollinating), so I tried pollinating R. rosifolius instead (only to find that a windstorm tore the flower clean off several days later). Back to square one, I'm gonna give it another shot both ways, while the plants are still flowering. With any luck, something will take while I still have the chance.

[Caesar]

Update: My first two attempts failed. The supposedly pollinated flowers dried up. I managed to crack open two more flower buds today, and applied more pollen (which didn't stick). I'm thinking of moistening the flowers tomorrow before applying the pollen with my fingers (hopefully some of it will stick that way). I'm not seeing the stored anthers release their pollen. Should I rub my fingers as I apply the pollen to help them do so, or would that damage the pollen?

I'm not giving up. I'm gonna make this hybrid work if it kills me! jejeje   

[Solko]

I'm sorry to hear the crosses didn't develop into fruits... This is often the case and cross pollination is dependant on so many factors to succeed. There is a good chapter in the book Breed Your Own Vegetable Varieties by Carol Deppe on doing wide crosses between different genera. All in all that book is really the best book I have ever found on amateur or backyard breeding. It has all the basics and a lot more refined techniques to try at home, in order to overcome pollen incompatibility.
Good luck on the next try!

A good trick for your cross would be to take fresh pollen of your chosen father plant and set it aside. Then also take pollen from the mother plant - you don't want it to fertilize the flower, but you know that this pollen is compatible. Then you either repeatedly freeze and thaw that mother pollen during a whole day, in order to kill it. Or put it in the microwave several times until you are sure it is dead. Then mix it with the live pollen of the father plant and apply it to the flowers.
The idea is that you kill the pollen you don't want, but keep all the activating enzymes in your pollen mixture. That could trigger the style in becoming more receptive to the foreign pollen and will give you higher chances of fertilization.

Good luck!

Solko

[Caesar]

I'm sorry to hear the crosses didn't develop into fruits... This is often the case and cross pollination is dependant on so many factors to succeed. There is a good chapter in the book Breed Your Own Vegetable Varieties by Carol Deppe on doing wide crosses between different genera. All in all that book is really the best book I have ever found on amateur or backyard breeding. It has all the basics and a lot more refined techniques to try at home, in order to overcome pollen incompatibility.
Good luck on the next try!

A good trick for your cross would be to take fresh pollen of your chosen father plant and set it aside. Then also take pollen from the mother plant - you don't want it to fertilize the flower, but you know that this pollen is compatible. Then you either repeatedly freeze and thaw that mother pollen during a whole day, in order to kill it. Or put it in the microwave several times until you are sure it is dead. Then mix it with the live pollen of the father plant and apply it to the flowers.
The idea is that you kill the pollen you don't want, but keep all the activating enzymes in your pollen mixture. That could trigger the style in becoming more receptive to the foreign pollen and will give you higher chances of fertilization.

Good luck!

Solko

Wow, thanks for the info! I've bookmarked the book (no pun intended) to buy it later. As for the sterilized pollen, is that what's known as Mentor Pollination? I had been looking for info on doing that for so long, and I couldn't find anything. It seems so counter-intuitive, it hadn't occurred to me that the mother's pollen had to be sterilized to work. I'll definitely be trying it next time (it's a little too late for now, with this attempt already underway). How many times do I have to freeze & thaw, or nuke it, for it to work? And for how long?

If this attempt doesn't work, I'll have to wait for the next flowering season. No matter, I'm patient, and this little trick should help me on my way.