Seed head poor in seeds

[MAB]

Hi guys, this year at sowing time I opened the seed heads of last season's Virginia (2022) and to my surprise very few seeds fell out of each head!
What could have happened?
Last year I cut and hung for the cure the stem of the top part of the plant 11 weeks after transplanting (141 days from sowing), the plant I bagged had been in flower for 4 weeks. Then I left the stem bagged until the stem dried completely. Finally I saved only the biggest and darkest pods.

Furthermore, these days I have noticed that some pods have brown spots:



I would assume that the pods have been a bit sunburned, in fact they are in full sun throughout the day.

Here is an image of a floral head that is in the shade during the hottest hours:



As you can see none of the pods have a brown spot.

Any thoughts? Thank you.

 

[deluxestogie]

Most varieties of tobacco produce "open" blossom heads, so they are always fully exposed to the sun. Ideally, the seed pods are collected only when fully browned on the plant. These then should be dried thoroughly, before seed extraction and storage. Storage conditions must be dry. Storing the extracted seed, rather than the whole pod, requires far less space, and removes any pod-borne pathogens.

You speak of brown spots, but have not shown them in the photo. Your tobacco variety is not stated.

Potential problems:

• bud worms (they usually leave a tiny hole in the side of the pods, and eat the seed)
• premature harvesting
• inadequate initial drying
• inadequate storage (exposure to heat and moisture)
• insect access to stored seed

Since the average tobacco plant can easily produce a quarter-million seeds in one season, there should be no shortage. My usual practice is to dry the harvested seed heads indoors (still bagged) until late fall or early winter, then extract and screen the seed. Some pods are always empty. Some pods contain thousands of seeds each. By storing the seed, rather than the whole pods, I know that I have seed.

Bob

 

[MAB]

Thanks Bob!
The strain is Virginia Gold and here are the small brown spots:



Well, maybe it's normal that there are these little brown spots, I've never looked carefully before now!

Anyway, I had saved the seeds for “routine” but my intention was to use the 2018 seeds (an amazing season) but when I took the tupperware (my seeds bank) out of the fridge it was half full of water and the water was one bit entry into many ziplocks.
And it was lucky that the 2022 seeds were still in the tray!

I have now taken a seed head out of the tray to check:



These are the seeds that come out simply by crushing the head:



It seems like a sufficient quantity of seeds… now I suspect that by bad luck at the time of sowing I had crushed the three or four poorest seed heads!

 

[deluxestogie]

I store my tiny Ziploc seed bags (2 x 3 inches) within a plastic "dry box" (sold in sporting goods stores), and accompanied by a bag of desiccant (sold for coin collectors). Although I keep all the dry boxes in a seldom opened, small refrigerator, DRY is more important than cold. Studies in non-electrified areas of India have demonstrated that completely dry tobacco seeds can remain viable for up to 40 years. I have had no difficulty germinating my own 10 year old seeds. Dry, dry, dry.

The brown spots at the bases of the blossoms are abnormal. I just scrolled through over 60 of my closeup images of tobacco blossoms, and saw no such spots on any of them.

Example:

Bob

EDIT: Also, if you open a cold container, before allowing it to warm to room temperature, moisture from the air will promptly condense inside the container.

 

[MAB]

Thanks Bob, that information very informative!

I think I'm buying new tupperware (plastci box): the one now is a reject from my wife's equipment and therefore doesn't seal well.
And I put my future tiny Ziplocs with desiccant bag in it. But I'll do like in India and I won't put the plastic box in the fridge.
The fact is that my refrigerator occasionally makes ice in the upper part and my wife cuts off the electricity to defrost it. Evidently a bit of water got into my poorly sealed plastic box.

As for the small brown spots on the pods, this is the first time I've noticed them but it's also the first time I've looked at the pods very carefully. So they may have been there in the past few years as well. Maybe it's little sunburn.