Me and a few other locals are starting a participatory plant breeding project to develop two new watermelon varieites. One of the target varieties would be a citron cross, so I'd love to participate! I got some citron seeds from GRIN, but they don't seem very red (do they lose color with age?) but starting with selected specimens would probably be even better. I'm in Canada, so we are also crossing that with small short-season varieties and cold resistant germplasm.