Author Topic: Seed sanitation to avoid introducing pathogens: Phytophthora in Tomato  (Read 202 times)

Ocimum

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To avoid diverting the original topic on blight in tomatoes, but continue the very important topic of disease transmission through seed, here a new topic.


Any suggestions on seed-sanitation counter measures that might be appropriate? For example, would freezing kill spores in/on seeds? Would dehydration?

Each species has it's weak points. Freezing beans against the bean weevil is well known.

About Phytophtora in seeds: I do not know what the weak points of the oospores of the species are.

They survive drying in soil
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-3059.2000.00515.x

However, they seem to die if the soil containing them reaches more than 40įC. Maybe heating is a solution?
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3059.1995.tb02719.x
(it does not tell if the soil was dry or wet. Makes a huge difference...)

Lactobacillus may be a way to reduce Phytophthora in tomato seeds
https://www.ijcmas.com/vol-3-1/Jiahui%20Guo,%20et%20al.pdf
I know people who swear about soaking seeds in whey before sowing.

gmuller

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Heat treatment is a method I have seen in books, for general pathogen control, but I haven't used it.
My sous vide machine would probably do the job.
GM

B. Copping

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I was a bit suprised at the half-strength household bleach, and the time period reccomended (compared to what Iíve seen in some books); but Iím inclined to listen to these pros. :)

https://tgrc.ucdavis.edu/seed_germ.aspx

gmuller

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Interesting. I've always been very cautious with bleach around seed - like, i never use it.
gm

Andrew Barney

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I have used the TGRC treatment method for germinating wild tomato seeds with success. 50% water 50% household bleach. But I have my doubts about the need for it for germinating galapagos species other than as a disease fighting measure.

triffid

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UV-C light may be another method of effective decontamination on small scale. There's also evidence that it increases biotic stress resistance in the resulting plants.

Andrew Barney

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UV-C light may be another method of effective decontamination on small scale. There's also evidence that it increases biotic stress resistance in the resulting plants.

Could you provide some scholarly articles or peer reviewed documents to support this idea? There were a few of us discussing UVC on the homegrown goodness forum for potential mutation breeding.

triffid

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Of course, I should have included references in my first post.

Hormetic UV‐C seed treatments for the control of tomato diseases  https://doi.org/10.1111/ppa.12987

UV Light Inactivation of Human and Plant Pathogens in Unfiltered Surface Irrigation Water   https://aem.asm.org/content/80/3/849

Water is obviously very different than the surface of a seed but considering UV-C has been shown to reduce Phytophthora in turbid mixture, and is employed as a commercial decontamination strategy for fruits and nuts with varying surface properties (https://www.dinies.com/english/uv-seed-disinfector.html) & (https://www.goodfruit.com/uv-light-controls-pathogens/), it would appear to be a promising process worth researching further.

Ocimum

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Plasma may also be a solution, but the price probably not in the reach of many of us, except with contact to universities...
https://www.sciencedirect.com/science/article/pii/S0168160516304664

It removes soem human pathogens, but seed borne diseases were not investigated.