You do understand that your requirement effectively cuts out many modern non-GMO seeds? One of the big advancements in the turn of the 20th century was heteros

You do understand that your requirement effectively cuts out many modern non-GMO seeds? One of the big advancements in the turn of the 20th century was heterosis, or the systematic exploitation of hybrid vigor. If you maintain two (or more) extremely inbred but different from each other germlines, but cross them to produce seed, you get seed that is much more heterozygotic than is naturally common. This seed is then dramatically more viable and productive. But if you replant what it yields, you only get very disappointing yield. That is, it has been normal for farmers to buy new seed each season from some provider that specializes in making very productive seed for more than a hundred years now. Part of getting developing countries to raise their agricultural productivity to modern standards is getting them to start doing this, instead of continuously replanting their old seeds.