old seeds and 'blind' seedlings - any correlation?
 

Growing 1000+ seedlings every spring over the last few years, I always wondered about why some (rare) seedling would appear to be 'blind' (with no growing tip). Most often I observe this is melon/watermelon seedlings, less frequently in tomato seedlings, and very rarely in pepper and brassica seedlings.

This year I had quite a few of these 'blind' ones, and could not help but notice that these are more frequent (from 20 to 100%!) in a batch that was started from very old seeds.

I am thinking that there must be a correlation between the age of seeds and the frequency of 'blind' plants. Did anybody else notice the same? Another theory is that the 'blindness' may be related to some degree of seed damage (which is likely to occur with the seed age I guess...).

Any thoughts/comments?

I thought this, too. Until this spring old seeds were the only place I had seen it. But I had several show up in my dwarf project seedlings. And those were all fresh seeds.

I am sure age is one cause, but it can't be the only one. Maybe this adds to Craig's theory of damage to the seeds in the mail by the equipment they are using.

I picked the first tomato today from my last dwarf plant to have ripe fruit. It was way behind because it started out blind. I kept it going until it decided to put out growth. It will be interesting to see what the plants from these seeds do. Could there be a genetic component to it?

____
Marjorie

[quote=Tania;99478]I am thinking that there must be a correlation between the age of seeds and the frequency of 'blind' plants. Did anybody else notice the same? Another theory is that the 'blindness' may be related to some degree of seed damage (which is likely to occur with the seed age I guess...).[/quote]

Yep, I have noticed the same as well. Older seeds tend to be more likely to be "blind" (no growing tip) for me, and are also more likely to have seed coats that just won't come off despite my best efforts to help them along after the seed germinates.

Tania,

Funny story - last season we had twins! 2 stems came out of 1 seed!
It didn't survive, but I tried with my best spit to help with the stuck seed coat.

Maybe the longer tomato seeds sit - the harder the coat - the less developed the seedling is allowed to get? I wonder ...

~ Tom

Twin "Stick":

[IMG]http://i37.photobucket.com/albums/e94/tomstrees/Tomatoes%202007%20Start/Start2007Cont-11.jpg[/IMG]

Over the years I've dealt with a lot of very old seeds and some years I think I see a correlation with seed age and blind ones, and other years not.

Same comment for stuck seed coats.

Other than tricots or similar, it would have to be an abberation of the same gene, or a similar gene that causes a blind seedling and I have problems accepting that it's always a specific phenotype that would result on all blind ones that appear whose origin is there b'c of seed age.

And no, I don't have any better suggestions to explain the phenomenon.:)

The other association that I've made and so has Darrel (Fusion) is that the seed viability of heart shaped varieties is not as great as non-hearts and that still holds for me.

[quote=Tomstrees;99513]Tania,

Funny story - last season we had twins! 2 stems came out of 1 seed!
It didn't survive, but I tried with my best spit to help with the stuck seed coat.

Maybe the longer tomato seeds sit - the harder the coat - the less developed the seedling is allowed to get? I wonder ...

~ Tom

[/quote]

Tom,
I only saw this type of 'deformity' once before. I guess twins are even more rare than the 'blind' ones...

Not sure if the seed coat gets harder with seed age - I always assumed that it is the embryo that gets weaker (as it slowly consumes nutrients that are stored in the seed over time), and that's why it gets harder for the seedling to shake off the coat.

I've seen capsicums produce blind seedlings too. Last year quite a few from the same seed packet had the problem. Bit annoying when you only get 30 seeds in a packet. (Not blaming the supplier just commenting!)

I've had tricots do just fine. My experience is different from his. It seems I have a few every year but last year had way more than this year. I take them off when I transplant and never really pay any attention. JD

My tricots grow fine; neither magical nor cursed.

Never noticed saved seed from one carrying that trait on down the line.

john

Had a tricot growing next to a normal Coustralee, and after a few weeks in the ground, you couldn't tell the difference because they both had branches and suckers growing all over.

my uncle steve seeds from 1992 gave me 3 plants with no growing tip. one is about 4 inches tall with a couple of bumps at the intersection of the cotyledons, so i would say age is a definite factor, but not the only factor that causes blinds. my only woodle orange from seeds 4 yrs old has one normal looking leaflet with no further development likely to occur. might be a different problem there.

keith

Tom -- I had a twin this year for the first time ever. I didn't think to take pictures when it was smaller, so it might be a little hard to see in this photo from today. One of the twins has been a runt since the beginning, and continues to be. It's a healthy plant though.

[IMG]http://img.photobucket.com/albums/v446/Sherry_AK/twin.jpg[/IMG]

A truly triploid tomato (three sets of chromosomes instead
of two) is useless. Their genes are generally too scrambled
to produce fruit, and even if they did, selfed fruit from the
plant would produce sterile seeds. (This information is from
a research paper that I found online when I was first curious
about whether triploid tomatoes were generally found among
the heirloom or commercial cultivars. I don't think I bookmarked
it, but it had detailed illustrations of what all goes wrong with
reproduction when all of the cells have 3 sets of chromosomes
instead of 2.)

But tri-cots are not necessarily from completely triploid plants
in my experience, even if true triploids start out looking the
same (3 cotyledons). All of the tri-cots that I have seen
from seeds that I sprouted reverted to normal di-cot behavior
at the first set of true leaves (leaves developing in pairs)
and produced a plant very close to if not identical with
the original cultivar.

Apparently there is some other, more localized mutation
that can cause triple cotyledons to develop that is
a less radical change than the seed having 3 sets
of chromosomes instead of the usual 2.

A quadruploid (4 sets of chromosomes) would have a better
chance of producing a non-sterile, viable plant than a
triploid (but no guarantee, you just have to grow it out
and see what happens). Like tri-cots, 4 cotyledons is probably
not a sure sign that every cell in the embryo is quadruploid.
(It could be a local mutation that only affects the cotyledons
themselves.)

It's fishing season, so I'm going to open a can-o-worms.

"Old" by itself, to me, is not the very best description for seeds. As an example, A T'ville member sent me 42 year "old" (but still fresh!) seed, last year. It came from a deep freeze at Auburn U. When the freezer broke down, things got handed out.
Thanks VGary.;)

This year, with the seed (Ace 55) now 43 years old, I test germinated it. They came up in three days.

And, as an example of fairly old but not so fresh seed, I tested the last of my oldest purchased seed, AGP. The seed is a minimum 6 years old. 12 days to germinate, three seedlings, one blind, one normal. And the third... has a first true leaf and then appears to be headless after that, although I should know if it is, in a few days. Out of 300+ seedling starts, these two AGP's are the only problems I've had.

Gary