All apples in an entire orchard share the same DNA (except the DNA in the seeds) if they are the same apple variety, since apples trees are propagated by grafting - they are clones of the original seedling that produced the distinct apple variety.
The DNA in the seeds is unique because it is a mix of both parents - even if both parents are the same variety, the process of reproduction juggles the genes.
Which opens up the concept of true and false fruits and for apples, being false fruits, this is technically not correct. (I was once told that pedantry was the life blood of GQ)
Fascinating. I vaguely recall learning a bit about plant life cycles at that age, but all of it struck me as profoundly weird and I quickly dumped it. Including this alternation idea; thank you for showing me something new and really very interesting.
The wiki on this seems very thorough and to a decent level of detail with lots more depth readily linked. There’s nothing controversial about:
AIUI, in most higher land plants that alternation, if it occurs at all, is an organism-level thing, not a fruit-level thing. So even if, e.g., apple trees do meaningfully participate in alternation (which is unclear to me) any given tree would produce individual apples that are all the same in this factor.
Obviously modern agricultural practices and carefully engineered plants are very far off Nature’s “design point” for plant reproduction. Whole fields of clones, each sitting on single or multi-grafted root stocks which are themselves identical clones of different cultivars and in some cases different species is not what Mother Nature intended.
Which is not to say it’s Eeeevil, just to say it’s human-made (human-tweaked?) enough that it need not conform closely to how wild plants work.
It seems like if people are saying that alternation of generations exists in, for example, flowering plants, the haploid stage is the pollen/ovum. Pollen does behave sort-of-like a distinct organism - that is, when it lands on the stigma, it typically grows a root-like pollen tube structure down to the ovum in order to deliver its genetic material - in some plants (ginkgo, I think), the pollen produces motile sperm that perform the function.