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Old March 30, 2018   #8
bower
Tomatovillian™
 
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Join Date: Feb 2012
Location: Newfoundland, Canada
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Age of seed definitely can be a factor. So where the nominal seed age is not the problem, I usually think about environmental conditions in storage or in transit that reduced the viability of the seed or 'prematurely aged'. Random things can happen - I'm thinking of a nice batch of pepper seeds I'd saved, that got left on the table where the sun shone on them... I got zero germination from this batch, and had to resort to an older seed lot.
OTOH I wonder if seed process can also play a part. I experimented one season with fermenting tomato seeds in a ziploc, didn't add any water, maybe not enough air either. Those seeds were slower to germinate and had more helmet heads as well, than any other lots of seed I've saved. I went to a mason jar system instead last year, adding water again, and got good seeds that germinated quickly and few helmets. So it's possible that the type of seed process can have an impact on germination too. Why?
- is it the rate of imbibing water that's affected? I always thought old pepper seeds were just dryer than the fresh and took longer to imbibe... or, is it that the seed coat fails to soften as it needs to do for the seedling to break out and seed to be easily shucked?
There are enzymes and hormones involved in the germination process, so it could be an effect of my ziploc process that affected for example levels of ABA in the dormant seed. Or that the RNA for seed coat softening enzymes was affected? Or just a physical effect on the seed coat that hardened it more than the usual.
I think i'm more confused about this than when I started.
I do think that genetic differences exist, but they're certainly minor for seeds that were saved the same way and germinated in the same conditions. Not more than 48 hour differences I've seen, and the not-so-good seed process affected all genotypes the same way, pretty much across the board.
This is interesting:
natuurtijdschriften.nl/download?type=document;docid=541131
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