I don't know about Moreton Hybrid but I dehybridized Ramapo F1 many years ago and last I knew many folks were using the F6 or F7 generation and perhaps more and all was well.

Below I linked to the page of Ramapo, the OP, at Tania's great tomato data base site.

I see no seed source for it but I know it's been passed around at several message sites.

If interested you might want to see if anyone has it by going to the seed exchange here at GW, for at least one place.

I have no fresh seeds I can send you and as you can see the dates on the page below you'll know why. I did it when it was announced that Ramapo F1 was going out of production, and of course Rutgers reintroduced the F1 several years ago.

The person Ed Ryan referred to in the page was at one time a large commercial tomato grower in NJ and he felt that my OP selection was just as good as the original F1.

Carolyn

Here is a link that might be useful: OP Ramapo