Back on the old QDMA forum I had a thread about apple trees that some people loved and have asked me to post on this forum so that they would have access to the scientific information that I spent many hours researching. When I started that thread I had a question and a hypothesis. In science, hypothesis is a tentative statement about the natural world leading to deductions that can be tested. If the deductions are verified, the hypothesis is provisionally corroborated. If the deductions are incorrect, the original hypothesis is proved false and must be abandoned or modified. Hypotheses can be used to build more complex inferences and explanations. "Fact" in science is an observation that has been repeatedly confirmed and for all practical purposes is accepted as “true.” Truth in science, however, is never final and what is accepted as a fact today may be modified or even discarded tomorrow. By the time I finished my research, it was my personal opinion that my hypothesis had been proven as fact. Note: The following is where I pieced together (cut and pasted parts of) the information in the original thread. I realized later that I should have copied the whole thread, but I didn’t do that. What I have included is what I consider to be the important information. Note: The forum only allows me to enter 10,000 characters at a time, so I have to make multiple posts to get all of this done. The Original Question I posed with partial research: Why do we have so many issues (especially with fireblight) growing some apple cultivars that in the past gained such high acclaim and have been propagated for decades and maybe even centuries? My Original Hypothesis with partial research: Every heritage apple cultivars started as a full sized tree on its own natural rootstock and was grown from a seed. When someone recognized a particular tree as something special and worthwhile for propagating, they were observing that tree growing on its own natural rootstock. Most of the time when that tree was propagated (by common country folks in the 1800s), it was from rooting a cutting of that variety or digging a root sprout, and the new tree also became a full sized tree that was essentially a clone of the parent tree in all respects at the molecular level. When you read the wonderful stories about a particular old heritage apple variety, you are reading what was written about its performance and attributes as a full sized tree like I have just described. Many of those varieties were just as wonderful as the words that were written about them. However, some of those varieties – even though worth propagating – were not so great in terms of fireblight resistance, and the stories about them were exaggerated to some degree. They were good enough as full sized trees to be continued as a cultivar, but they were very marginal in disease resistance. But did the common country man at that time really care? There was no reason to care as long as they were producing enough apples and good enough apples to please the people who grew them. I believe that it is many of those cultivars like I just described that give casual growers like most of us on this forum trouble today. Why – because we are not growing them as full sized trees but as dwarf and semi dwarf trees. They were marginal or borderline in their natural state, and when we started grafting them and growing them on dwarfing rootstocks we tipped the scales (possibly in multiple ways) to the unacceptable side (for us) due to several factors that I am getting ready to talk about. Note: Keep in mind that what I am talking about here is for the casual growers like I believe most people on this forum are and want to remain. The main difference between us and the 1800s homesteader is that we are also concerned about producing apples for deer and other wildlife. Both groups (us and them) want/ed to also grow apples for human consumption, but for them it was more of a necessity. My discussion here is not for the professional grower who must go to great lengths to spray and perform special activities beyond the scope of the casual grower in order to produce apples of supermarket quality. I suspect that with enough spraying and care that almost any apple could be successfully grown, but I really have no personal interest in becoming a commercial grower.