I guarantee you, in a SHTF situation with no food, you will find people digging up those Sunspot sunflower tubers and eating them as they ARE food and called Jerusalem artichokes. They do taste like water chestnuts and that's not a bad taste or people wouldn't eat water chestnuts. It is a nutritious food - since you know where they are, maybe you can make a business of selling them when people are starving.
As far as saving some regular potatoes for the next season, that is easier to do in states that have a genuine cold season to keep the potatoes alive/dormant. It's difficult to keep them until the next season in the south as it is warmer in the south. I grew up in real east Texas and Father could keep some under the house during the winter. Farther south makes it more difficult.
Info. on potato seed from Iowa State University:
"FROM: Iowa State University Horticulture & Home Pest News"
"OCCASIONALLY gardeners are surprised to find small, round, green, tomato-like fruit on their potato plants. These fruit are not the result of cross-pollination with tomatoes. They are the true fruit of the potato plant. The edible tubers are actually enlarged, underground stems. Normally, most potato flowers dry up and fall off the plants without setting fruit. A few flowers do produce fruit. The variety ‘Yukon Gold’ produces fruit more heavily than most varieties.
The potato fruit are of no value to the gardener. Potato fruit, as well as the plant itself, contain relatively large amounts of solanine. Solanine is a poisonous alkaloid. The small fruit should not be eaten. Since potatoes don't come true from seed, no effort should be made to save the seed."
If you ever grow a potato from these seeds you have to process, let me know how that turns out.
Here’s a simple method:
“Potato
While usually propagated vegetatively, the potato can be grown from seeds which occasionally form on the plants. Let the seed balls mature, then squeeze the seeds into a bowl. Add water and pour off the floating debris, saving the seeds which sink to the bottom. Grow the same as tomato seedlings.
Some of the smaller nightshades, such as cherry and currant tomatoes, tomatillos, ground cherries etc., can be processed in a blender and treated the same as potato seeds. “
http://www.naturallifemagazine.com/9504/seeds.htm
In a SHTF scenario, it probably doesn’t matter if a saved seed breeds true or not. I have saved and planted hybrid tomato seeds and they sprout and bear. Some of the plants breed true, some don’t and bear true to the progenitors, instead.
I suspect the University/Extension article was speaking to commercial farmers. That’s a whole lot different from personal gardening. For example, I have gotten busy and just placed fresh tomato seeds on a paper towel, no fermentation, no washing. They stuck together, so I pried a few off and planted them, indoors, with bottom heat, in the late winter. They sprouted, they grew, they survived transplanting and they bloomed and set fruit. Back in the 1990s, when our local climate was warmer, I had one variety of cherry tomatoes survive a mild winter and volunteer right where I had planted them the previous year. I think the name was Tiny Millions or something like that.
The original wild fruits were managed and planted and eaten by generations of primitive people. It obviously was done in the past and can still be done, today.