I will be saving seed this spring from some older samples. Since they were very large to start with, I should be able to still get fairly good populations out of them.
This scenario is very common among seed savers. Often, a sample is saved until its viability begins to decline, and sometimes varieties are rescued from very old packets with just a few viable seeds left.
Ignoring the possibility of drastic inbreeding, what is the longterm unintended results for the variety? What are we selecting for by doing this over and over again?
I can imagine lots of different results
more stored food in the seed lager seed greater overall vigor more seed protecting toxins slower growth harder seed coats longer dormancy slower germination
These could all be good or bad, depending on the crop and situation. A lot would depend on whether the seed is the edible part or not.
Any thoughts on whether this effect exists, and if so, how to use it in a directed manner?
Post by philagardener on Feb 10, 2014 19:50:48 GMT -5
It sounds to me like you primarily may be selecting for seed that remains viable longer. For my own purposes, that might be good!
Stored food and larger seed may be under different pressures as many seeds have almost immeasurably low metabolic rates. Toxins might not be an advantage in the absence of predation pressure. Harder coats, slower germination - those could act against the ability to revive after storage. So that leaves vigor, longer dormancy and resiliency. Doesn't sound too bad to me!
A bigger cost might be growing out seed every year, after year, without selecting for longevity! Then you might have to keep doing so or lose the line. High maintenance crops!
Post by philagardener on Mar 5, 2014 7:06:14 GMT -5
Does anyone know how precipitous is the loss of viability can be as a lot of seed ages? I would guess that it is some function of overall longevity (i.e shorter lived seeds like onions and carrots might lose a lot of ground with an additional year, whereas longer lived seeds might dwindle more gradually).
Leaving seed too long without germination testing in any case is a potential hazard. Looking at all those vast seed stashes some of you have, how do you avoid " templeton 's quandary"? (It seems like drying and storing in a freezer delays the inevitable, but do you test regularly to plan grow outs, or do you just have so many things that you simply save and hope for the best?)
Post by 12540dumont on Mar 5, 2014 20:01:40 GMT -5
For me the answer lies in the type of seed.
For example, I never keep parsnips longer than a year, or onion seed for longer than 3. They just really lose vigor after that.
One of the things I try to do with corn and beans, when they get to be ridiculous is to eat some of them down to a manageable number. You can use onions and radishes as sprouts.
Some things don't languish long in the freezer, some things don't get used all that often. I'm having a drought year, so I'm being very careful with what I plant. That said, I've carefully sorted out seed of things I know were drought tolerant.
It really helps to make a note of weather on your seed packets. For example, if I have 3 packages of saved Cherokee Green tomatoes, noting that one was from an especially hot year, I may plant that one during a drought season. It also helps to make note of WHEN (early or late) that you harvested seed from something and compare these in the future. For example, gee did I actually save seed from something that bolts early in my garden? Great, lets plant it during a cold wet season. Harvested late? Great, let's plant that during a drought season, maybe it will hold on.
Too many squash? Try dividing up your seed among 10 packets, keep 2 or 3, and send an entire squash collection to someone else on the board.
Keep an eye on what others are experimenting with and mail out a chunk of seeds.
When I do a trial, sometimes I set aside what produced really well for me and send the others on to someone, someplace where they might do better. Or, someone who's fiddling with a project. Many folks here have generously sent me a pack of carrots or onions for my trials. Of these some did great here, others not so great. I've tried to send lots of carrots back out. But I still have many in the seed fridge. Okay so their biennial so that means I don't have to save carrot seed for maybe 3 more years.
A few years ago, Joseph sent me radishes and turnips. I planted a few of them over a couple of years and then last week I got a wild hair and said, "I wonder how Joseph's turnips and radishes will do in this drought?" Sometimes seed planting is a matter of intellectual curiosity.
I have found several seed library's that will take anything I know I'm never going to use again....like the squash that makes 50 pound whoppers. Sounds great until you have to lift them, and then they don't fit on the shelves. So the Richmond Library received all my GIANT squash.
Don't tell Dar, I'm also planning the same thing with Giant Watermelon. Bigger is not always better. Of course smaller isn't either!
Somethings I don't even bother saving seeds of, like Romanesco zukes. Why? I have 30 seeds in the freezer, that's enough of that variety for 5 years.
I do worry about some seeds though. I have enough tomatoes to try new ones for about 5 years...without even replanting the old ones. But hey, I like some of the old ones!
I got a Palmwoods tomato from Raymundo. On it, he noted the seeds were old. When I planted it this year, I double sowed them. And very few of those came up. (I've got 3!) Now, if he hadn't told me, I might have dawdled and never gotten any of them. I have a few more from Dr. Male & Dr. Dar to deal with next year. Some years its hard to choose!
Post by Joseph Lofthouse on Mar 5, 2014 21:37:46 GMT -5
There's lots of things that interfere with seed viability: rain, bugs, mice, heat, old age, etc... Pragmatically I handle them the same way: Stop planting the seed when it stops germinating. If I know a batch of seed is getting weak (or started out weak) I'll plant twice as many or three times as many or ten times as many seeds as usual. If they germinate too heavily I thin them. If they don't then I replant. Because I grow my own seed I often have a 10, 20, or 30 year supply of seed.
On most crops I regenerate the seed each year and plant fresh seed. As seed ages I bank it for a few years, and then eat it or feed it to animals.
Germination testing is trivial for me. Put some seeds in a damp paper towel in the germination chamber and check it 5 to 10 days later. I don't typically check germination on seeds that I'm planting for myself, only for what I'm sharing with others.
Silt/clay, high-altitude, super-arid, sun-drenched, irrigated-desert garden. Cold radiant-cooled nights. ~100 frost free days. Grow most of my own locally adapted landrace seed. GDD10C ~1300. Buy my book or subscribe to my newsletter at Lofthouse.com.
Post by philagardener on Mar 8, 2014 7:55:29 GMT -5
Thanks, everyone, for sharing your experiences with this! I am still working out strategies to archive and regenerate things (before it's too late); seems inevitable once you have been saving seed long enough. I am still in the early chaos stage.
You can also get longer storing seed by saving really well grown fully mature seed from healthy plants.
I have wondered about that, specifically with sweet corn. The past two seasons I have took to digging up my seed corn plants after the silks have died and the rest of the crop has been eaten. I started doing that cause I wanted the seed ears to stay on the stalk as long as possible but they were taking up space I could otherwise reuse and they were always in danger of critter attack.
They are basically being transplanted, I crowd them in big tubs with a tiny bit of chicken poo along with garden debris and a little soil and keep them watered. Growth is over so they don't need space and I can leave weeks longer till the husks and leaves are browning. Anyway what I'v noticed is instead of shrunken up seed (even though those will grow the next year) I'm getting nice plump seeds, more like a flour kernel except with little crinkles all over the surface, even when SE genes are involved. Not enough experience with it yet but I bet these seeds will keep longer than the ones picked earlier.
Many plant breeders have voiced concerns about the big seed banks might be getting changes in accessions just by inadvertently selecting for seed longevity. But what are you going to do if you are saving hundreds of thousands of accessions? Bluemeadow is right. Very old seeds do have a higher proportion of mutations. That is well documented. But generally the mutation numbers are small. Experiments with this date back to before it was found that you could get lots of mutations from radiation and chemicals. It could be that very old seeds have mutations because they have existed long enough that natural background radiation has had time to mutate them. For myself, I seldom save seeds very long. I don't need seeds that I don't grow for food or flowers every year. I do save extra in case of crop failure. Otherwise, I am selecting every year. If I'm not using my newest seeds, I'm not using my best seeds. That's assuming my selection is effective.