They are certainly not forgotten but sweet potatoes are an excellent root crop that stores very well without refrigeration, actually better without than with. The warm climate of Texas should also be a very good environment to grow them.
john muckleroy jr wrote:I am researching forgotten root crops and not forgotten root crops that would be great for an area with no refrigeration that store well
What sort of storage environment is available? In very cold-winter areas, root cellars basically are refrigerators, though they require more active management. Most root veggies store fine in a root cellar, though onions and garlic seem to prefer dry conditions over damp, even if it is warm (as opposed to cool). In cool-winter areas, many root crops store fine right in the ground. The other question is what kind of growing environment is available. We have had great success with parsnips in a variety of storage conditions (including wintering them in-ground over winters that hit -40), but they prefer a cooler growing season, I think.