Then maybe there’s not that much to worry about. But if you wanted to create an SI fruit tree landrace and are specifically worried about this issue, then one solution would be to ask people from cultures who already do it. Also another way to protect a population is to now and then introduce some individuals from another landrace, keeping the genetics topped up. This is actually very common in traditional landraces so far as I can see. For example in the traditional landracing cultures I’ve looked into like in the Andes, Africa, and Laos, there’s specific culture to share seeds over long distances. The crops I specifically remember in this context may not be SI, some specifically have low rates of outcrossing like rice, and potatoes were another, tetraploids and diploids - I don’t know if they’re SC or SI or both but there’s a lot of outcrossing I think. I don’t think the aim was for the new ones to cross with the old, but this was in a context where a family might be growing something like 6~10 different landraces of the same crop, and considerably more across the whole village, so some mixing would be bound to occur through outcrossing, and this would mean some level of genetic input to the landraces over time. Also while the potatoes were grown clonally, there would be some percentage of ‘volunteers’ emerging from seed and if their tuber phenotype were similar enough, they’d then become part of the landrace, even if not knowingly. So even such predominantly clonal populations were topped up genetically over time.
With modern landraces we can do this consciously, and some people specifically advise this. Also like I said, if there’s more than 1 person interested in the area, you can share the work, which means you don’t just have to rely on 1 person to take care of an entire population. And even with annual crops, you can keep a much bigger breeding population than you can grow in 1 year if you simply stagger seed production. You can plant different seed batches in different years, harvesting seed from each, so that your seed stock is much more diverse than just a single year’s seed harvest. So, these are 3 ways of increasing/maintaining higher diversity.
Interesting. Makes sense to me.
Yes, I did understand your point. I hope you also understood mine. The clonal population is like a library. Similar to a genebank - genetics frozen in time that can be accessed and used to revive or create new, living dynamic systems. This is why genebanks are so useful for creating new landraces. Even more so now that so many landraces are being decimated, pushed to extinction by commercial entities.
Well, not necessarily. I know in mainstream modern breeding, there can be an attitude of looking for specific genes, then trying to get just that specific gene into a line one is working on, and using DNA markers and so on. One doesn’t have to do that with a landrace approach. Did you watch the video I shared? That’s a great example. He started that evolutionary population of wheat with 2,000 varieties! That’s quite extreme and it’s totally possible to start with a far smaller number, especially with fruit trees. But anyway it’s an approach which is quite different for hunting for single genes.
And yes, as I keep saying, there will be an initial decrease in diversity. That’s totally fine! That’s a normal part of natural selection.
Great!
I find that extraordinarily unlikely. Most specifically because I have personally seen and eaten yuzu of numerous different phenotypes, fruit varying considerably in colour, size, skin texture, flavour and so on. I have even eaten 3 very different yuzu sold by 1 single farmer.
To back up my direct experience with an academic reference, here’s a quote from the paper ‘Cultivar identification of ‘Yuzu’ (Citrus junos Sieb. ex Tanaka) and related acid citrus by leaf isozymes’:
The center of origin of the ‘Yuzu’ is presumed to be the upper region of the Yangtze river and was spread widely into the southern areas of China. It was introduced in Japan from China via Korea during the Man-yo period, about 750 AD (Taninaka et al., 1981). After introduction, ‘Yuzu’ produced various progenies which are cultivated as local cultivar. They formed a special group of acid citrus in Japan. Cultivation of them is more commonly performed in Japan (Swingle, 1967).
[…]
There was much confusion concerning the interrelationships among the ‘Yuzu’ and related acid citrus cultivars, since many local cultivars were considered to have arisen during long cultivation periods (Taninaka et al., 1981). These cultivars have originated in a variety of ways including selection from open pollinated populations and mutation from existing cultivars.
You can also find a variety of named yuzu cultivars in Japan, and Japan isn’t even the only place to search for varieties - they are popular in Korea also, for example.
Personally I love to just squeeze the juice into water and drink it with nothing else added. Also lovely squeezed over food or used in sauces etc. The skin is also prized.
Yes. Though I have heard of some nice successes also. The same goes for crossing with green tomato species. It can take a few generations to get a delicious landrace, as I mentioned before.
Not necessarily. For example one landrace approach is to wait for the 3rd generation to start selecting for flavour, the first 2 letting the environment do the selection.
Well I know for a fact that that is simply not true for other species. I know of people who have extended the range of numerous species via the method I have been describing. I know it is far less common as a method, but I know it works. And that’s in the modern context. But this has been very common throughout history even. Not necessarily by this method of deliberately starting with a hybrid swarm - by slower methods, by which we have seen domesticated crops spreading across the globe. But starting with a hybrid swarm represents an accelerated method of that basic principle through which the various domesticated species have spread into new areas for as long as farming has existed. The method of mapping genes and all that, is extremely new. And most certainly not the only way!
Sure, I never said it was easy 
On what evidence are you basing that view? I would say that in general, landraces differ from heirloom varieties in particular on exactly that point - there is an obsession for keeping heirlooms ‘pure’, frozen in time since when they were often bred by breeders and sold in the seed catalogues, some back to the 18th century. But landraces are often far more fluid than that, and often containing many genotypes even within SC populations. The focus of traditional farmers in times past was on phenotype selection, not genotype. And in addition to that, as modern breeders, we can consciously maintain higher rates of genetic variation in our landraces. Joseph Lofthouse is a good example of that. And Salvatore Ceccarelli’s method of ‘evolutionary breeding’ to establish populations adapted to local land whilst maintaining high genetic diversity within populations, is another great example. I encourage you to watch that video I shared if you did not already watch it.
You seem to be ignoring all of my explanations that if wanting to create a new landrace, I’m not suggesting taking one single landrace that is not suitable for your environment, and hoping it will adapt. I’m saying get a whole bunch of different landraces, cross them all, and let your environment select from the hybrid swarm. Then also maintain a fair degree of genetic diversity after the initial settling, so that the population is better equipped to continue to adapt as the environment continues to change gradually. The latter step is anyway the same as how natural populations continue to adapt, as they have been from the beginning of life itself.
Starting from scratch domesticating an entirely wild species is a different matter. But I could give you many examples of extending the range of domesticated species using the landrace method, both by bringing together many varieties already domesticated, or by crossing with wild species. I myself even just a few minutes ago ate a delicious F2 (or F3?) tomato that was S. lycopersicum (domestic tomato) crossed with S. galapagense, a wild tomato with no history of being eaten by humans. 50% wild, entirely delicious, and grew with much less disease than all my pure domestic tomatoes. That particular one has undergone I think even no selection at all so far! I’m not saying everything is that easy - it’s not. But what I am saying is that it is wrong to think that this process has to take thousands of years.
No that’s not how I was defining it. But anyway, in the specific context which Richard complained about, I was referring to Indian people growing Indian landraces in the land they had formed those landraces in. I cannot imagine what issue he would have had with my usage if he had actually been reading this thread.
There is a spectrum. Take a look at traditional landraces and you will find phenotypic variation. For example you can find potato landraces in the Andes where the tubers will look very similar but there may be differences in the phenotypes of the leaves or flowers etc. It is up to us as breeders what phenotypes to homogenise or not.
So when you realise that it is in fact a spectrum, you can decide for yourself where you want to draw a line on that spectrum for your use of the word ‘landrace’, and I don’t really mind where you do that, but it is the content of the discussion which is important.
It’s also worth bearing in mind that higher diversity of phenotype is important during the earlier stages of creating a new landrace. You can narrow down phenotypes as you go on. It’s only really a landrace after a certain amount of adaptation and genetic and phenotypic settling has occurred. But we are after all talking about creating new landraces. That is a gradual process. And it’s really worth settling on a level of variation that may be higher than most traditional landraces since our climate is changing now so much more rapidly than in past centuries. So, it’s better to create and maintain landraces with a higher than normal level of adaptability, so, accepting a higher rate pf phenotypic diversity can be very useful for that. But like I said, it’s anyway always a spectrum.
Are you saying that after having experience with creating your own landraces, or having studied examples of people who have done so? I am guessing perhaps not. Since it directly contradicts all the evidence I know of. And I have interacted with quite a few people who work on creating landraces.
If that were the case then we should expect all wild OP populations to be homogenous. Remember how I mentioned a single accession of a single SI wild tomato species can have more genetic diversity than the entire planet’s collection of heirloom tomatoes? That would seem a good counter example. And yet they have had hundreds of thousands, or millions, of years of interbreeding.
Also what’s your point, do you disagree with what I said, that in an SI or sufficiently outcrossing OP population, the diversity is dynamic? If so then I will just agree to disagree because I think it’s just a very plain fact.
I don’t mean to be rude but your thinking seems very black and white. As if you can only imagine 1 possible way, and want to deny any other possibility. For me a far more rational response would be ‘Maybe yes, though I personally feel a better and/or faster option would be if NC State University had started an extensive modern breeding program’.
I also would have thought that my example of the plum landrace would have had at least some impact, but it seems everyone has ignored that. To remind you:
It’s hope that the genetics already exist, perhaps in ways yet to combine in a suitable manner, in the population. That’s the key. Diversity drives evolution. So, starting with maximum diversity in an outcrossing population is the fastest way to accelerate evolution. If you want to get an introduction to this kind of method, the video I shared is a great place to start, or even taking this free course would really help in getting to grips with some of the principles:
Which is why I said about not selecting for too many phenotypes at once. And also not even selecting for taste for the first few cycles when extending the range of a species. And also be willing to have some phenotypic variation in the product, like I mentioned with squashes, you can go for consistency of flavour and size, so that it is a reliable product for cooks, but allow variation in colour and shape and leaf and so on. Using these principles can really speed up the project leading to rapid adaptation.
Yes. Though landracing tetraploid potatoes can be great! But it can be nice to run OP and clone populations in parallel, keeping your favourites going as clones but still growing from seed in another plot every year or even every few years. You can keep saving the best new varieties as you go along and you might be gradually replacing your clonal populations with such new varieties, and you’re also protected that way from too much viral buildup, not having to depend on endless clonal populations. But anyway, it was the ploidy level that made me think diploid Japanese plums might be a better idea for landracing rather than European plums, not just in terms of ease for making interspecial crosses, but also due to simpler breeding even if using the single species to landrace.
Yes. I would actually recommend getting numerous different varieties, crossing them all to make numerous F1s, then crossing all the F1s with each other. Then plant all the resulting seeds out, and let the ‘race’ begin, so to speak.
Ok so here is where I differ from Joseph Lofthouse. He recommends planting everything out, letting it cross, planting out all seeds harvested, do the same again, then in the 3rd year start some selection for taste. My own approach is to take great care until one has the hybrid swarm, and only then expose them to the local pressures. This means generating the greatest genetic variation possible before exposing to selective pressures.
With his method at least some plants which did not survive to give seed, can still be in the mix as pollen donors for the fruits of other plants that did give seed. But anyway for me it is more logical to be more active - hand cross everything, make sure it all survives. And I do this by speed breeding indoors.
With fruit trees that’s not so simple obviously. But thinking aloud here, one good way might be to graft all candidates one wants to use, onto a tree or trees, in an area where they are all likely to do ok. Manually cross them all, grow out the seeds, graft them again, cross them again, harvest all the seeds, and then plant all those seeds in the target location. You could even do that one more cycle before moving to the target location, or let nature do the cross pollinating even, though manually would be more thorough, giving higher diversity.
If you wanted you could even at the 3rd or 4th round of grafting, select only the acceptable tasting fruits, and plant all their seeds. Or plant them all in one plot and the others in another, since they still might be valuable and still might give good tasting offspring. And like I mentioned, you might want to get others involved - you could split the seeds among even 10 or 100 people!
Another reason why this method can have advantages over the modern academic method.
That sounds oddly fear-based. People making new landraces doesn’t mean the world of clones is under threat! It’s really the world of landraces which is under massive threat from modern breeders’ work, so many countless landraces already having disappeared. So I think you should have nothing to fear. Also where do you think so much of that precious ‘rare genetics’ came from? 
There’s a hint at answering that in my above academic quote of plum landraces.
Very different direction to what I have been talking about, but… maybe creating triploids could be an avenue to explore? They’d be infertile… hmm, would fruits even form? But I mention this because, if I remember correctly, triploids can be fitter, isn’t it? Like isn’t it the triploid taro that are the only ones suited to more Northerly climates?
Are you sure yuzu is bitter? Sour yes but I thought bitter was one special thing about it being that it lacks it. Or was that just the rind?