Well, you are entitled to your opinion. However, in my opinion, the impacts of epigenetic effects are inconsistent and unreliable. They are certainly not "fully measurable” or reliable, and that’s the reason why fruit breeders don’t focus on them. It’s hard to make use of them in fruit breeding the real world. If you look at most any major fruit breeding program, the things they are most focused on tend to be genomic selection, or things that could potentially improve phenotyping, either in accuracy, speed, or quantity.
In my opinion, there are excellent reasons for this. However, it does not appear that further conversation on the topic would be productive, so I will just leave it at that.
For anyone interested in this topic, here’s an article on the effects of ethylene on plant development. Jean-Baptiste Van Mons made use of ethylene exposure (in the form of rotting fruit) while developing his pear cultivars, including ‘Bosc’ and ‘D’Anjou.’
Below is one of the study’s highlights—the effect is quite dramatic.
Detailed investigations into thale cress plant tissue also revealed that the levels of glucose, sucrose, and starch shot up by 266%, 446%, and 87% respectively, pointing to greater productivity from photosynthesis.
I find Luther Burbank’s use of what we would now call epigenetic effects particularly interesting. After Burbank noticed that grafting alone could sometimes produce changes in traits such as leaf color, he attempted to maximize these effects in whatever ways he could. He began to hang parasitic plants around his grafted trees, because he observed that these plants seemed to increase unusual growth responses.
We now know that some parasitic plants are capable of horizontal gene transfer, though this was entirely unknown in Burbank’s time and would not have informed his interpretations or methods.
I’d almost buy that he was attempting to breed mistletoe as ornamental if he didn’t only hang it from his fruit trees and didn’t also have dodder hanging from them as well. The “breeding mistletoe” story was likely made up out of necessity after his mistletoe became mildly invasive in the immediate area.
I’d like to approach this from a different angle. Breeding requires a lot of time and effort. If profits cannot be secured through rights or patents, only charity amd non-profit would to this.
However, the current legal system does not adequately protect epigenetics, or in other words, varieties that fall outside of Mendelian inheritance. We are already struggling to protect perennial crops like grapes and apples, which can be easily propagated asexually. In practice, only F2 hybrids can fully safeguard the interests of companies and shareholders.
Until there are comprehensive legal and institutional protections in place, we are unlikely to see much progress in epigenetic breeding .At least on the commercial side.
I know that some parts of the world don’t protect all epigenetic changes, but the legal system in the United States—and in several other countries—does recognize and protect non-Mendelian forms of inheritance, such as cytoplasmic inheritance.
Of course, these protections don’t prevent people from asexually reproducing patented plants—but that limitation applies to all crops, not just those that fall outside Mendelian inheritance.
This is interesting. It seems that the ethylene exposure approach matters and can have both positive and negative impacts (continuous and under light stunted the plants but exposure in the dark and tapering provided benefits). I appreciate that these things are being looked at and find them interesting.
I use the micro plastic tubes that some seeds come in. I collect the pollen, leave the lid open and stand it up in a small container of silica sand for a few days to dry. I then close the pollen tube and cover the container with a lid and pop the whole thing in the freezer. I usually have multiple tubes standing in the sand. The silica keeps the moisture out of the container in the freezer. I have used two year old pear pollen successfully but I don’t like to rely on that so I collect every year.