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.
@Eme since you asked I’ll explain some of the terminology I was using (and more). If anything is unclear don’t hesitate to ask questions
allele: a specific variation of a specific gene on a chromosome
heterozygous/heterozygosity vs homozygous/homozygosity: organisms typically have two or more of each type of chromosome (see ploidy) homozygosity of a gene in an organism is when all the instances of the gene are the same allele in an organism, while heterozygosity is when there’s two or more different alleles for it present in the organism. Inbreeding tends to increase homozygosity
Ploidy: so you may have heard how humans have 23 types chromosomes and how we have two of each type of chromosome (well females do, male humans have a Y chromosome instead of second X chromosome). Ploidy refers to the number of chromosomes of each type that an organism has. Humans, having two of each are diploid (di meaning two). While having more than two of each chromosome is lethal to humans, the same isn’t true for plants. The prefix in front of “ploid” indicates how many of each chromosome there are. For example diploid, triploid, tetraploid, pentaploid, and hexaploid mean there’s 2, 3, 4, 5, and 6 of each chromosome respectively.
Apomixis: is when plants produce seeds that are genetically identical to themselves regardless of the father. A form of asexual reproduction (although pollination is still required for some species the pollen doesn’t contribute genetically to the seeds)
it can be range from obligate to facultative, with obligate meaning all the seeds are produced by apomixis while facultative means some seeds are produced by apomixis while others are produced sexually
For purposes of breeding it is quite frustrating because it means when you pollinate flowers of an apomictic plant (a plant that reproduce via apomixis) the chances of the seeds produced being hybrids is quite low
Thank you! I’m familiar with the top half from human genetics; the bottom half is very helpful. I get lost with the implications of diploid and tetraploid for breeding and the nuances you all are calculating and adjusting for with your selections. It’s really fascinating, and I’ll keep reading and hopefully start to catch on. Will not hijack the thread further.
I’ve heard that removing petals can potentially be an effective way to stop flying pollinators from visiting flowers. I’m going to be trying it in public places where people might mess with bags if I put them on flowers.
For anyone interested in fruit breeding and genetics, the links below contain a selection of some of the most interesting articles you could find on these subjects. This collection was curated by Karl King.
There are articles by many of the great fruit breeders and scientists of all time, including quite a few that aren’t available anywhere else online. Some of these articles absolutely blow my mind and offer fascinating insights into fruit breeding and genetics.
Anyone who checks them out should use critical thinking and keep in mind that some of the material contains outdated scientific theories and ideas. Even so, there’s a tremendous amount to learn from these articles.