I'm in the process of writing a piece for my blog about hand-pollinating potatoes, to encourage others to try making their own hybrids. I have a few points I'd like to clarify to make sure I get it right.
At what point do you emasculate the flowers? Is it the same as with tomatoes, where you emasculate when the sepals start to open but the petals are still shut - like this:
Do you emasculate only the flowers you want to use, or do you need to get rid of any other anthers on the same cyme to avoid self-pollination?
Do you pollinate on the same day as emasculation, or leave it until the flower opens? At what point does the stigma become receptive, and how can you tell?
At what stage are the anthers at their best for pollen collection?
And some questions about selecting parent plants ...
If a variety usually flowers but doesn't set berries, is that an indication that it has sterile pollen, or is it worth trying to self-pollinate it by hand?
If a variety is pollen-sterile, will it set berries when pollinated with a more fertile variety, or do you come across female-sterile varieties too?
OK, I've watched all the videos now and they're full of fascinating stuff - but I haven't found anything about the practicalities of hand-pollination (unless there's still any I've missed!) I can write the article based on my own limited experience and observations but it would really benefit from some input from those with more experience than me.
I was intrigued though that Tom mentioned Pink Fir Apple and said that if anyone is thinking of making crosses with that one, he can give suggestions. Yes please Tom! I have some Pink Fir Apple in the garden right now which is just about to burst into blossom! Suggestions very welcome. I notice the Pink Fir Apple blossoms have a shorter style and more knobbly stigma than any of the other potatoes I grow.
Other varieties I have in the garden at the moment to experiment with ... Salad Blue, British Queen, Sharpe's Express, Mr Little's Yetholm Gypsy, Highland Burgundy Red, Marfona, Congo, Red Craigs Royal, Négresse, Foula Red and two types of Shetland Black (the commercial type and the one actually grown by Shetland crofters, which are very different varieties). Also the diploid Mayan Gold. Plus all the TPS seedlings! I'm hoping to get some interesting hybrids out of that lot.
Post by Tom Wagner on Jun 15, 2010 18:24:24 GMT -8
The potato flowers you have in the photo can be emasculated and pollen applied now and also in a few days.
Try to make those crosses while you can... Here are some interesting Pink Fir Apple (Rose Finn Apple) aka
ANYA =DESIREE x PINK FIR APPLE COLLESSIE =PINK FIR APPLE x SHETLAND BLACK HARLEQUIN =CHARLOTTE x PINK FIR APPLE MOULIN ROUGE =DESIREE x PINK FIR APPLE
I suggest using the PFA as a female...I think the pedigree info above must list the male first... Oohhh. Shetland Black is in your collection ...I had that a few crops ago...many TPS of it yet. I am hoping to get some F-2 Highland Burgundy crossed to the Harlequin this summer.
The pollen parent that has the most pollen is the one to use as the male parent most. I think you may find it hard to find pollen on the PFA.
The most prolific berry setter I've ever had in my garden is Salad Blue, so I've mostly been using that as a male parent. Mayan Gold is also a good pollen producer, and I've made a few experimental crosses between them (both ways) to see if any will take.
I tried pollinating some Pink Fir Apple buds with Salad Blue a few days ago, but the pollinated buds fell off! Never mind, I will try again.
Shetland Black is interesting. I bought some from a commercial source a few years ago, enjoyed it, and wrote a review of it on my website. And then somebody who lives in the Shetland islands wrote to me and said did I know it's not the "real" Shetland Black which the crofters grow? He kindly offered to send me some tubers of what he claimed was the authentic local type, and sure enough it was a very different variety. It has charcoal black skin, rounder tubers with deeper eyes, and the foliage is completely different too. I'm waiting to see if it will flower and set berries (the commercial one had a few flowers but no berries). He also sent me the Foula Red, which is another local Shetland variety with a red skin, but very low yielding!
Post by Tom Wagner on Jun 16, 2010 11:19:42 GMT -8
Regarding the Shetland Black. I am not surprised. Here at the USDA they have a potato clone that has the name Early Ohio, but it is nothing like the Early Ohio I grew as a kid. Theirs is white, mine were pink. i think some of this difficulty is with tissue culture mix-ups.
The problem you have with Pink Fir Apple is much of what I have experienced especially in past years. The blossom fall off too soon, and little pollen can be collected to take to a flower holder like Blue Salad.
Some varieties are like that ...you can't use the flowers or pollen.
Sorry if this question is covered on the videos. I'm on dialup and download times are prohibitive.
How long is the pollen viable? Tomato pollen is only good for a couple of days if refrigerated, but potato flowers seem to stay open longer. I collected anthers off of my Skagit Valley Gold today and will have a container of loose pollen tomorrow to apply to my Thumbed Nose which is a small plant with flowers just starting to open so I don't want to use dead pollen if I use this SVG pollen for too many days.
Post by Tom Wagner on Jun 21, 2010 16:49:52 GMT -8
I suppose I should retry the storage of pollen again for this year. especially since my plantings are scattered over April, May, June, and it looks like July is when most of my potatoes are going into the ground. It has been that wet this year and windows of opportunity to plant escaped me.
I normally use fresh pollen since I have had so many varieties available most of the time. My understanding of potato pollen is that it may be viable for 10-14 days at room temperature at fairly low humidities. Refrigeration may extend the life a bit and studies of below 0 fahrenheit can be good for a year! I used to put gel caps of pollen in the refrigerator and freezer with variable result, and I really do need to collect pollen from the SVG x Moe Joe types since they have been blooming for the last couple of weeks and with many potatoes yet to be planted.....
I have dried potato flower clusters on the dashboard of my vehicles for years...hot sunny conditions desiccate the flowers into near herbarium specimens...and the pollen can be collected days later. I did this for years with Yukon Gold potatoes. Most of the time the variety does not make flowers and I have to scan a field of Yukons to find a few flowers and then dry the clusters to build up the amount of pollen I needed for crosses. The drying was an accidental event due to laziness at first then intentional.
Oh, BTW, here is a link that shows some vital information
That is great news since the varieties you sent me are growing at wildy differnt rates for some reason (wet soil setback possibly), so the bees I was going to relie on for mixing them up probably won't get the job done this year.