I disagree, open source ag is completely compatible with hybridization. And if open source couldn't somehow deal with the benefits of hybridization, then open source ag is not a route we should follow.
Farming is a transformation of inputs into food. It's not about seeds and propagating seeds every season... that's just an attachment to a practice like being super attached to, say FTP as the only way to transfer files and deploy a website.
Open Source Ag is completely compatible with maintaining two strains, crossing them, and then distributing those seeds. Having widely distributed access to these seeds, and information about them, gives the chance for more innovation in the crossing, too. The question is whether somebody can get compensated for the efforts in discovery...