Trusmadiensis is either lowii x macrophylla or macrophylla x lowii and thats it. If you cross lowii x tm its a lowii x tm the only difference would be that the cross is 3/4 lowii and 1/4 macrophylla.
There is no way in hell to get tm from crossing lowii x tm. There is no such thing as just because the parents are the same its a backcross and thus a tm. How a bout ventricosa x lowii x ventricosa? According to your reasoning its still a lowii x ventricosa because of backcrossing with vent and the parents are the same? The same applies to briggsiana
There is no way in hell to get tm from crossing lowii x tm. There is no such thing as just because the parents are the same its a backcross and thus a tm. How a bout ventricosa x lowii x ventricosa? According to your reasoning its still a lowii x ventricosa because of backcrossing with vent and the parents are the same? The same applies to briggsiana