Home gardeners seem like a pretty good option here. For more regular vegetables, this is already a thing that exists with seed libraries and exchanges, and programs that preserve heirloom varietals and sell the seeds to gardeners. Buying these seeds is basically just a way to help pay for the continued cultivation by the breeder (unfortunately, unless you
really know what you are doing and are quite careful, preserving a specific variety on your own in a home garden is difficult-verging-on-impossible, despite what 1000 online guides to "seed saving" will tell you).
The harder thing is the grains, since those typically require so much more work to get from the plant to the plate. I've looked into growing my own wheat before (I already have a large garden and have enough space that I could theoretically grow enough wheat to cover a substantial portion of my annual flour use), but the small scale/DIY options for threshing, sorting, grinding, and sifting are just not quite practical (for the level of effort I'm willing to put in, which I'm quite sure is higher than most home gardeners).
If a small scale solution to harvesting and processing wheat can be made relatively cheap and simple, I'd bet you could get home gardeners to support the continued cultivation of these varieties in the same way that they frequently support heirloom tomatoes etc.
Again, to be very clear, the gardeners themselves are (mostly) not doing the preserving. The plants home gardeners grow are a dead-end genetically (usually not being preserved at all, and even when they are, almost certainly representing mixes of several different varieties), but buy purchasing seeds from the larger scale growers, they are paying to support the continued cultivation of those varieties.
The harder thing is the grains, since those typically require so much more work to get from the plant to the plate. I've looked into growing my own wheat before (I already have a large garden and have enough space that I could theoretically grow enough wheat to cover a substantial portion of my annual flour use), but the small scale/DIY options for threshing, sorting, grinding, and sifting are just not quite practical (for the level of effort I'm willing to put in, which I'm quite sure is higher than most home gardeners).
If a small scale solution to harvesting and processing wheat can be made relatively cheap and simple, I'd bet you could get home gardeners to support the continued cultivation of these varieties in the same way that they frequently support heirloom tomatoes etc.
Again, to be very clear, the gardeners themselves are (mostly) not doing the preserving. The plants home gardeners grow are a dead-end genetically (usually not being preserved at all, and even when they are, almost certainly representing mixes of several different varieties), but buy purchasing seeds from the larger scale growers, they are paying to support the continued cultivation of those varieties.