This thread just sort of evolved, and I'm too lackadaisical to keep the threads properly sorted unless it's really important, then I'll prune and transplant threads to their proper categories.
Eventually we hope to have "ne plus ultra" (every feature of our best lines in one package) sorghum but it might be a while.
Sorghum sometimes spontaneously shows up perennial because it spontaneously crosses to a perennial relation, S xhalapensis, that is itself a stable tetraploid hybrid between domesticated Sorghum and one of its perennial cousins from India, S. propinquum. The hybrid, "Johnson Grass", is coldhardier than probably either parent, occurring all the way to southern Canada. It spontaneously developed in Mediterranean Europe a long time ago.
Back-crosses occur spontaneously because weed sorghum tends to show up in the same parts of the world that domesticated sorghum is grown.
Bountiful Gardens had a sorghum that is fitfully perennial but I do not know what the quality of the grain is like. Since few people eat sorghum straight (except those who are buying gluten-free bread mixes that contain it), it often does not occur to the vendors to specify the grain quality. The better-tasting ones are typically described as either "white sorghum" or "yellow endosperm".
Syrup is another human food use for sorghum, and those are usually separate lines, because they are bred to have juicier stalks with less fiber, for easier extraction.
