I had this conversation in a thread with Har a few years ago and we believe they are not true to seed. Since, I’ve fruited grafted and seedling Giant Yucatán in La Habra CA and I couldn’t tell the differences. I have 6-7 varieties ,1.5 year old seedling saramuyos, growing right now in CA and they’ve bloom this year….trees are too small to hold, maybe next year. Another added bonus is they are as cold hardy as cherimoyas and atemoyas in La Habra where sugar apples struggle. Do a search in the forum on saramuyos and you’ll see the leaves totally different of any sugar apple. Saramuyos are supremely delicious as good as Aussies atemoyas and California cherimoyas. You can also see the leaves on my Instagram.