Why do virtually all the Internet sites that offer suggestions for growing pecans from seed expect you to eventually graft a varietal onto the seedling? There is a vague reference to sterility as the reason for grafting. Is sterility such a problem? Or is the problem one of lack of genetic trueness to the parent of the seed? Otherwise, should I expect these 'from seed' seedlings to produce healthy ornamental or commercial value trees when mature? Who do you trust to sell seed true to variety?
There is too much genetic variability in seeds. Trees could end up being good producers or lousy producers and many people do not want to wait until a tree seedling is mature to find out - a waist of years if the seedling ends up being a poor producer. Selective breeding will only take you so far - there is always going to be variability. If a grower or homeowner wants a good pecan with good production, then they will want to graft a proven producer's scion onto the seedling rootstock. I have attached a visual prepared by a friend for an example.