My experience with community, and local production, is that people do what they love doing, and share the results of their doing with their neighbors. If someone in the community loves grafting apple trees, and they graft a lot of them, and take them to the farmer's market, or take an ad out in the local paper, or sell them to local nurseries, or get a reputation, then other members of the community may buy and/or plant those apple trees. Some members of the local community may become enamored of grafting, and likewise start grafting trees.
I don't worry at all about creating or maintaining a social network regarding my walnut breeding program. I send walnuts out into the community. They grow or die. People come and go. I watch the ecosystem in my community, and when mature seed-bearing walnut trees show up, I bring the nuts to my farm to start the next generation. Doesn't matter to me if they are descended from my trees or not. They are walnuts that produce seeds in our climate. That's the primary selection criteria right now.