Seed size relative to viability/longevity?

I have a completely unproven (in my own growing) theory that suggests larger seeds would hypothetically last longer in storage i.e. still germinate after a longer period of time than smaller seeds of the same type.  

For example, I recently cut open a candy roaster squash that had about 55 seeds that were fully formed & viable.  Approximately 10 of those seeds were very large, darker in color, and fully mature.  We'll say 30 of the remaining seeds were of average size, but smaller than the largest ones.  Finally, the last 15 or so were small sized, but still plump, hard and viable.  

I'm now certain that if I'd let the squash sit for another month or more, more seeds would be larger and more mature, but once cut open...  

My thought is that the largest seeds within the fruit would sprout and grow with the most vigor because there's more "fuel" within the seed to get a strong start.  By that same token, if there's more reserved growing power within the seed, does that equate to a longer shelf life due to the seed having more stored "energy?"  Conversely, would the larger seed consume its reserved "energy" at a faster rate than a small or medium sized seed to remain viable?

I ask these questions in the interest of choosing which seeds will remain viable for the longest period of time for the purpose of future backcrossing options, as I experiment with my season to season growing.  Ideas?

Sounds like it'd make a good experiment!

Save and sort a bunch of extra seeds, and after whatever storage time period you like to use, set them up on a wet towel or something so you can see their germination.

I think those are some really interesting observations Cy and would be awesome to experiment with.

Cy Cobb wrote:My thought is that the largest seeds within the fruit would sprout and grow with the most vigor because there's more "fuel" within the seed to get a strong start.

I've been thinking the same based on what I've been seeing recently. It seems to give them an initial vigor boost to get started, while later vigor may be more dependent on soil fertility or genetics, but at least initially they seem to start growing quicker.

By that same token, if there's more reserved growing power within the seed, does that equate to a longer shelf life due to the seed having more stored "energy?"  Conversely, would the larger seed consume its reserved "energy" at a faster rate than a small or medium sized seed to remain viable?

I ask these questions in the interest of choosing which seeds will remain viable for the longest period of time for the purpose of future backcrossing options, as I experiment with my season to season growing.  Ideas?

I tend to think that seed size may not have a huge effect on long viability, since there are a lot of small tree seeds that can remain viable for years in the soil. But I think it would be a really neat thing to test.

However I have noticed that the harder seeds tend to store a lot longer.

My squash seeds have ranged from pretty flimsy to very hard. It's interesting that the harder seeds seem to correlate with squash with a harder shell and therefore they store very long. The flimsy seeds also seemed to produce the squash that didn't keep long at all. I also wonder if the harder seed coat is more effective in "sealing" the seed and therefore increasing its length of viability.

I'm selecting for longer storing squash so I'm guessing my seeds will probably end up being mostly very hard.

I'd love to hear how yours turn out!

Thanks Steve, It would be a long 8-10+ year study for the squash seeds from what I'm reading.  Most sources say they are viable for 6-8 years (Maximas).  So, if we can find someone with an old stash of seeds already, we would be time ahead if they could segregate the largest seeds in the batch from the rest, then do a germination test on the lot to see 1) if the larger seeds have a better germination rate than the average sized seeds, & 2) overall, germination rate of aged seeds.  

The easy answer is to just save all seeds, then when you want to grow them, see what sprouts.  However, if seed storage space & efficient planting (again due to space restrictions) are important to you, this could be some useful information.  For example, if I have 100 Maxima seeds, & I decide to save the largest 20 as a reserve/backcross stash to add generations later, it would take up less seed storage space.  While that's not a lot of saved space for one squash, if you are keeping seeds from many individual squashes, it can add up.  The nice thing about this method (if it works), is you can give away or trade your excess seeds to many other people that want to grow them within the 6-8 years with no issues.  In this example, that's 80 seeds to swap/share & at 10 seeds given per person, that's 8 happy recipients!

The other benefit to narrowing down the longest viable seeds lies in garden space.  If you had those same 100 seeds for 10 years, you'd have to either plant all of them to see what comes up, or try paper towel germination testing, then plant those.  If you have a lot of land, & can afford to have plants scattered all around, I would choose this method.  However, in my experience with doing the paper towel germination testing on old sweet corn and old bean seeds, you risk introducing fungus/bacteria to the few that might sprout from the many that have gone bad, even with sanitizing the seeds prior.  

It really all depends on your breeding goals.  Sometimes you want to isolate the seeds from one mother fruit to see what traits the unknown fathers put into the offspring, and other times you welcome as much diversity as you can get.  No wrong way of doing it here, just seeing if there is a predictable way to determine the longest lasting seeds upfront.