Topic: Saving potato for seed

[Jesse]

I'll be digging up all my Cara's today and want to put some potatoes aside for planting as seed next year. Is this a good idea or should I rather buy seed potato fresh next year? If I do set some aside what should I choose, large, medium or small ones, or does it not matter?

[redimp]

It is a very bad idea as you do not know what diseases they may be carrying.  You should only ever use certified seed potato.

[tim]

Yes, indeed.

On the other hand, I tend to save known 'clean' tubers of eg Pink Fir.

And when I do, it's the 'egg' sized ones.

[Jesse]

Tim, when you say known clean, how do you know? Is it simply looking at them and if they look healthy they're okay? My potatoes have not suffered from any disease that I'm aware of.

[Robert_Brenchley]

I saved seed last year and it's worked. Obviously it's no good if your potatoes have had any disease during the year.

[john_miller]

Tim, when you say known clean, how do you know? Is it simply looking at them and if they look healthy they're okay? My potatoes have not suffered from any disease that I'm aware of.

A problem could develop if your potatoes were infected late in the season with a virus. While the pathogen may not have had time to cause the plants to show symptoms it may have been able to translocate through the plant and when the plant goes into active growth the pathogen may only then become apparent.

[Jesse]

Okay, so it's better to buy seed each year rather than using old tubers from the previous year. What is done to the shop bought seed then to ensure they don't carry a virus from the previous year?

[redimp]

Now that is a good question because I have absolutely know idea.  ???

[Jesse]

I found this, not sure if this process is followed for all seed potato certification. Unless I've missed something it appears that nothing nasty is put on the seed to certify it virus free. :)

http://www.oscs.orst.edu/potato/limitedgencert-final.pdf

[Robert_Brenchley]

There wouldn't be since poisons don't kill viruses.

[Jesse]

I heard somewhere that chemotherapy and thermotherapy is used on some plants to combat virus, perhaps this only applied to non-edible plants, I don't really understand what I read.

[organicartist]

Thanks for posting that link Jessevieve, I'd always wondered how seed potatoes were certified, but never gotten around to researching it.

[john_miller]

I found this, not sure if this process is followed for all seed potato certification. Unless I've missed something it appears that nothing nasty is put on the seed to certify it virus free. :)

http://www.oscs.orst.edu/potato/limitedgencert-final.pdf

I imagine that this still holds true but in the U.K. but it used to be most potatoes for seed were grown in northern Scotland where the incidence of aphids and other viral vectors are greatly reduced compard to the rest of the country. While the techniques described in the link are probably used to re-juvenate the stock on a regular basis I believe that the bulk of seed potatoes are still grown up there. The fields are inspected regularly prior to harvest so that any disorders can be spotted and any problems promptly dealt with. This helps to keep down the cost as the methods described in the link are a more expensive way of producing seed potatoes. I'm not sure how widespread this method is even over here. Potatoes for seed are also grown in more northerly climates (Maine in particular for cvs. adapted to the eastern U.S. or even into the maritime provinces of Canada) and then assay lots are grown out in southern states (mostly Florida on the East coast) overwinter to so that any disease infections can be observed and the stocks that it came from removed from the market.

[djbrenton]

It looks like certification only requires visual inspection

http://www.sasa.gov.uk/mediafiles/0D4FC6B4_F171_A665_B119434B0168B2C4.pdf

however, the integrity of seed decreases each year when regrown, so buying fresh seed tends to give better crops. Scottish certified seed originates from micropropogation then hydroponic growth before being multiplied in fields for up to 5 years.

[Multiveg]

I might have another go at saving "seed" from the potato-tomatoes. Forgot about them last year. When should I sow the seed?

[djbrenton]

http://www.bejoseeds.com/potato/guide.html