Hybrid Vigor

Hi all,
Julia Dakin asked me to create a thread related to hybrid vigor. The question at hand is to what extent landraces really perform comparably to hybrids. I have seen academics argue that F1 hybrids generally perform equal to or better than landraces, even under stress conditions.

I’ve looked for formal studies on this topic, but it’s very difficult to assess what little I have found. Scientific papers don’t generally go into extensive detail about the exact condition that plants were raised under. Some studies take a landrace grown in one ecoregion and evaluate performance in another ecoregion because they think they are ‘similar enough’.

Different researchers use different definitions of landrace, and for sure some landraces are going to be more genetically diverse than others. I’ve even seen some definitions of landrace that disqualify if you intentionally try to improve genetics or if you intentionally crossbreed genetic materials from offsite.

So it’s hard to really evaluate or compare the academic studies that are out there. I was curious to hear any anecdotes about your experiences with the performance of hybrids vs. more genetically diverse crops and if there are more reliable studies out there.

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If a landrace is done properly ideally as many of the plants as possible are hybrids, so it would be surprising if a known f1 hybrid did better than the unknown hybrids inside landraces

As a farmer and a bit of a genetics nerd I might have some explanation of hybrids and hybrid vigor that is more useful than the science-ese speak.

Hybrid = race horse

Who needs a race horse? People who race horses or breed them. Kind of like the saying about some degrees produce 90% teachers and 10% jobs that will ever do anything with the degree.

A race horse is kind of the idea of a lean, mean, hard working machine bred entirely to do one thing really really well. Run fast, win races. For anything else it’s just an expensive horse. If you want yard pet horses you don’t need a race horse. If you want to ride trails you don’t need a race horse.
A race horse is bred to be an extremaphile (sp?).
I don’t live at the deep deep ocean bottom next to volcanic vents with extreme heat and water pressure. So I don’t need plants and animals that have to handle that. But there are plants and animals that can.

If you want to grow vegetables that are near machines you want hybrids. The most all the same size and at the same time. The most reliable DTM exactness. The most reliable flavor. The most reliable growth habit for your acres and acres of tomatoes that aren’t going to be individually tied up and trellised and pinch the suckers…
You want vegetables that come the closest to fitting the mold of planning out the year knowing exactly what days you’ll be harvesting and the trucks come to take it.

In a home garden we don’t need that. We can choose to trellis and prune tomatoes. We can pick different harvests spread out through the growing season. We can have the 2 tomatoes every week through the season plants. We can also grow some Determinant plants that will harvest close together to make a big enough close harvest to can all the sauce we want to do in a couple days. We aren’t beholden to you signed a contract and must have X pounds of this exact shape and size ready for pick up every week.
I think there are some market gardeners here so you’ll know that bit more than me but I imagine it’s the same.

My answer to what is hybrid vigor…
When you have two breeding lines that are bred to be the best of these traits you have bred out everything else. You have to always work hard to keep breeding for health and hardiness.
When you cross breed the lines the offspring do better than either parent. The lines may achieve like 90% on the traits you’ve bred for and will keep breeding and chasing it higher. But the hybrid of the pure lines has all the genes recombined, all shuffled and resorted. This produces much more vigor than you have in either parent.
The offspring would score like 150%! They are getting the best reshuffle of the genes you bred so hard for in both lines.

But…
Hybrid vigor is a once off. Breeding hybrids to each other gets you everything from 10% to 80%. All the reshuffled genes are now being reshuffled again and you’re getting lots of not great matches on them. You’re seeing all the stuff that’s been bred to not show up in each pure parent line.
So when you score them on productivity it’s a fail compared to the reliability of the parents and the vigor of the hybrid. But it’s great for genetic diversity because you’re always reshuffling genes to find new combinations that don’t work and ones that finally get those couple genes lined up together so that they can… survive cooler temps… survive diseases or pests… etc.

Hybrids are only going to be the highest performers when your parent lines are very carefully bred pure. If you breed a mutt to a mutt, you just get another mutt.

You can only achieve the exceptional production of hybrids when you are very intensively breeding and managing exactly what is bred to what.

For example… Cornish cross meat birds started as a simple hybrid. A meaty father breed who doesn’t lay much eggs. A high laying mother breed. Hybrid produces a reliable meat bird offspring and takes advantage of the mother line laying lots of eggs to produce lots of hybrids.
Now Cornish cross is a whole different beast. It’s a multi-level program hybrid. The meat bird you can buy to raise is the end product.
There are two parent lines…
Four grandparent lines…
Eight great grandparent lines…
Sixteen great great grandparent lines…
And if you change anything the whole deal comes down. You cannot recreate the same production of a commercial Cx bird unless you play that exact game to develop one over… what 70+ years now? And if you don’t play the tight genetics, pure breeding, multi-level hybrid system… You will not get a bird to compete with the commercial Cx bird.

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The racehorse analogy is mentioned in the video and the instructor denies it. I also see this paper that claims good quality F1 hybrids are almost always better in almost all circumstances.

Racehorse and Workhorse hybrids may exist, but at a very low frequency among comercially available corn hybrids. Most corn hybrids are stable – that is their performance is
similar to most other hybrids and is not appreciably affected when grown in a wide range of
low to high yielding environments.
https://extension.soils.wisc.edu/wp-content/uploads/sites/68/2016/07/Lauer2.pdf

The following study shows hybrids outperforming landraces (in yield) regardless of water stress. Again some of these studies can be hard to scrutinize without more information than they provide though.

If it is true that F1 hybrids are racehorses, there’s a lot of data out there that is claiming otherwise. It would be good to understand what is going on, why these researchers seem to disagree with farmers.

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Interesting… hm… my experience is with animals and it’s definitely a thing with them. You can breed a small ewe to a real big ram and she’ll wean a lamb as big or bigger than she is!
One day I’ll have to sit and read up a bunch of these studies.
The other hard thing about the studies and papers is you don’t know who paid for it. A study can show anything you want done the right way. At minimum it can always give shadows of doubt on other studies, because that’s science it’s not perfect.

The sources you cite seem to be primarily interested in crop yield (under optimal or in some cases stressed conditions). Landrace development allows you to select for many factors in addition to crop yield. Some of them, such as nutrient density, may be inversely related to yield. So, in the last study you cite, do we know what the selection criteria were for the landraces (or for the hybrids, for that matter)? Also, were the landraces in the test grown out in the locations they were adapted to, or in the researchers’ fields?

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I totally agree that the goals of commercial breeders are more aligned with the needs of large scale farmers, trucking companies, food processing companies, and grocery stores rather than the needs of gardeners or small scale farmers. Flavor and nutrition are rarely even a consideration; science is much easier when you are just trying to make one number as big as possible. Studies are a bit all over the place here but there’s evidence to suggest landraces do at times taste better.

The results showed a strong preference by panelists for tomatoes of landraces than for commercial varieties and wild species.
Neuronal network analyses reveal novel associations between volatile organic compounds and sensory properties of tomato fruits | Metabolomics

Regarding the wheat study, they chose a subset from a portfolio of landraces called the Israeli Palestinian Landraces and grew them in a Mediterranean and ‘Near East’ environment. No further information about the exact location; the assumption being that the ‘Near East’ ecoregion is sufficiently uniform for a study and that Mediterranean climates are kind-of similar but an important center for wheat farming.

Incidentally, I did find a systematic review that suggests many landraces do perform better under stress conditions like drought, so maybe this is a controversial topic among scientists.

Increasingly landraces are being replaced by modern cultivars which are less
resilient to pests, diseases and abiotic stresses and thereby losing a valuable source of germplasm for meeting the future needs of sustainable
agriculture in the context of climate change.
https://digituma.uma.pt/bitstream/10400.13/3192/1/Cereal%20landraces%20for%20sustainable%20agriculture.%20A%20review.pdf

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Thank you for posting this video! I’m partway through it. Have to be honest, his Cargill association + promoting Hybrids in W. Africa caused me to have a negative knee jerk reaction, so I will stifle that and not be defensive, because there are a lot of interesting things to consider here and if I’m wrong about something I def. want to know about it. I’d like to drop everything right now and dig through some old books I know are relevant here about stress, fertilizer, and hybrids, (or at least throw some words at an AI poem generator and write something funny :slight_smile: but I am giving a presentation tomorrow which I have to prepare more for, so I’m coming back to this topic on Sunday, just wanted to say don’t give up on me.

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Oh I agree, there is some stuff in the course that I had a negative reaction to as well. I try to approach all learning experiences with both openness and skepticism, which is why I started this thread in the first place to suss out some of the conflicts between that (31 video long) course and the course you all have provided.

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I really enjoyed listening to this guy. Knowledge is knowledge, regardless of how it’s applied. I’m happy to absorb it no matter the source. On the screen it says lesson 10, I’m going to look up the rest and watch them too.

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It is important to note that not all landraces are genetically diverse. Many of them have been isolated and inbred until they’re little more than a locally adapted variety.

That would be my first question in addressing any scientist working on this.

“Define landrace.”

If the landraces they’re working with are not genetically diverse, it makes sense that the hybrids would outcompete them.

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I can only guess but that guess would be that many scientists would define landrace similarly to how Dr. Alan Kapuler does. To paraphrase, it is a population that has existed in a specific area for a very long time, in cultivation by humans but including or originating from a wild source. Examples would include the many landraces of corn that still exist in Mexico and other regions of South America.

They are, indeed, perhaps little more than a locally adapted variety. So now, the question to me, is why have they not been ravaged over time to the effects of inbreeding depression?

Although not the topic of that professor’s lecture I saw hints of an explanation for that. Those same hints might also help explain why some of my tomatoes and beans, being undiluted heirlooms continue to perform very well in my garden. They were heirlooms when I got them, and I’ve had them for three decades or more but still they produce.

I was able to obtain and plant one of those ancient landraces of corn from Mexico and it grew as well or better than any corn I’ve ever seen, and I’ve seen and grown a lot of corn. I suspect if I tried to maintain it in a pure form in small my garden it would eventually succumb to inbreeding depression, but I don’t know that. Perhaps after centuries of cultivation in that area of Mexico its heterozygous nature is locked, even in small populations.

The only landrace species in my yard and garden according to the Kapuler definition are the various wildflowers I’ve collected from a wide area but all within the Ohio River Valley of Indiana, Kentucky and Ohio. These in my estimation are beginning to border on the Lofthouse definition of landrace due my intervention in selecting for my preferences in flower color and form.

All of my mixed-up vegetables where I apply Lofthouse techniques of allowing the environment to do the initial selection are in my mind more of what Kapuler describes as a grex. Populations of hybrid and non-hybrid plants being grown all together years after year.

I don’t present any of this to be argumentative but rather just as a reminder that the same words may mean different things to different people. I think it’s important to keep that in mind when in conversation and reading. I can go either way, I just need to know how the person I’m speaking with defines a term so I can understand what they mean and if my definition is different to translate what I say to match theirs.

I apologize for rambling, it’s a habit of mine.

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In that wheat study cited above I’d be curious to redo the evaluation at source. By that I mean pay some farmers who actually grow the various landraces to put down some of the modern cultivars alongside their landrace and grow both as they normally would, harvest as they normally would, in fact do everything as they normally would (e.g., irrigate or not as they normally would, same with fertiliser, or a particular use of the straw etc) and get the farmer to do the ratings.

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The complaint i hear most frequently from industrial farmers about hybrids, is that they are susceptible to complete crop failures if conditions deviate from expected.

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I think there are many things to consider that affect results. First, I would assume all comparisons are done from current commercial production point of view with current commercial production in mind. Which is understandable, but slightly narrow starting point. Adding on to Kadance’s racehorse metaphor, it’s not only the racehorse that matters, but the track as well. Track in this case being commercial farming practices as well as the land. For example landrace might be adapted to farming without plowing/tilling and that advantage is lost with plowing/tilling when it’s compared to something that might not be as well adabted to growing without plowing/tilling. Then have to consider what is compared. As pointed out before, some landraces might be just little more diverse heirlooms. They still might have enough genetic diversity to adabt but it might take time. F1 on the other hand might be tailored for some disease resistance that used landrace doesn’t have resistance widely, but could adapt to. Adabtion to local conditions and practises should be done first before any comparisons are made. It might be true that F1 perform better on year one, but it might reversed by year 3 or 4. Landraces also keep adapting. Any year might possess challenge that F1 can’t overcome like a particular disease. Then it needs to replaced with some other F1 and it’s not like F1 are just done and that’s it. It takes years of evaluating to know it’s propertities and where it could be used. So these comparisons are more like comparing apples and oranges.

Unrelated to F1 compared to landrace, but had facebook acquitance send me some studies about melon/watermelon growing in Poland. It was just to compare some F1 and heirloom varieties how they grow with different transplant periods and with/without cloth. The thing is that I got similar results as best in that study. Their best was with longer transplant period, cloth most of the season and some weeks longer season in general than I have (I’m from Finland) and I had short transplant period with just week of cloth. First year I had mainly hardy varieties plus one melon landrace and second year possible hybrids, but what I is wonder why they werent using those vaieties? I think there was one watermelon variety I had, but others were what are common in commercial production. Maybe they have some disease resistance that is considered necessary for commercial production. So it might be same with your studies, that there are some parameters that favour F1 over landraces that either aren’t necessary or that could be adabted to over some years.

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I have no doubt at all, that F1 hybrids are best in many ways, maybe all ways, for the industrial farmer. That is from their point of view and for their purposes. Actually, the use of proprietary F1 seed barely makes the top ten list of my issues with industrial agriculture.

Other than occasionally mixing an F1 into a landrace of whatever crop I might be growing, very little of any of that applies to. I’m not an industrial farmer. I’m a back yard gardener. F1s are completely useless to me regardless of how they perform.

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The first landrace crop that I planted was Astronomy Domini sweet corn. It was planted, on the same day, in the next row over from an (untreated) hybrid sweet corn. Astronomy Domini germinated near100%. The commercial hybrid (without it’s required poisons) germinated about 5%.

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The woman here insists on growing hybrid sweet corn. It’s hard to find seed that isn’t treated but I insist that it not be, I don’t want traces of that pink stuff in my soil. It germinates fine as long as she waits until late May or early June to plant it. I plant my corn four to six weeks earlier and mine is selected for fast maturity so no issues with crossing.

The industrial farmers farther west sometimes plant their yellow dent F1s as early as I do, if weather allows them to. I don’t know if that seed is treated, or if a combination of its hybrid vigor and all the chemicals they dump in with it make the difference for it.

It’s amazing how beautifully that corn grows. I’m almost a little jealous of how it looks sometimes. Perfectly arranged, lush green fields stretching for miles, it really is a sight to behold. All on a perfectly dead canvas where the last of the topsoil blew or washed away decades ago. A lot of moving parts in that industrial machine, hope nothing breaks.

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That made me laugh but it’s also a bit scary when you think about it.

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I have been working on understanding this study because they analyzing some qualities beyond yield, and there is tons of data… but if you have already done the work to understand all the abbreviations and what is going on, it would be super helpful if you could make a little screenshare summary explaining this graph … I already tried that with my husband but didn’t get that far :slight_smile:

It’s possible I’ve spent too much time on books re: this topic and less on peer reviewed studies, so I’m happy to change that starting now.

In the meantime I have a few comments on what I’ve gone through so far.

I’m convinced that commercial hybrids are higher yielding than landraces overall, but I’m not quite convinced they’ll be higher yielding in challenging conditions. I’ve read too much other stuff to overturn that one so far, but I plan to keep digging.

The definition of Heterosis is: “the tendency of a crossbred individual to show qualities superior to those of both parents”

‘qualities superior’ is such a subjective term. In most cases that are written by people associated with modern breeding, there is an extreme focus on yield/productivity, to the exclusion of everything else. In the graph above they analyze quite a few qualities that go beyond yield, but I don’t see any of them have anything to do with ‘superior qualities’ according to a consumer (grinding qualities, disease resistance, flavor). In fact the obsession with productivity in wheat has arguably made it much less healthy/digestible (high gluten showing up as gluten intolerance in consumers). The higher the yield, the cheaper, the more we eat, the less healthy we are.

Landraces are farmer grown and selected, and farmers care about different things than industry, so it makes sense that the selection process for “superior qualities” is different. It’s possible modern studies/industry is comparing apples to oranges and calling them all apples.

I want to leave a few relevant books here that talk in depth about these issues,
Restoring Heritage Grains which in the first few chapters talks in depth about the differences between modern and ancient wheats. Interesting even if you aren’t interested in growing wheat (I’m not).

Shattering: Food Politics and the loss of genetic diversity.. This book goes into depth on what the effect of introducing modern hybrids was on communities around the world. Makes the case that hybrids are more like Holsteins cows: High yielders, but without corresponding high inputs they yield less (or die). This phenomenon caused a widening income gap for the farmers that bought into them: The farmers that could afford the irrigation, fertilizer, and pesticides did get much higher yields and got richer. The farmers that had no access to credit had lower yields than before because they could not afford the corresponding inputs needed to get the higher yields. I think that the resources posted here dispute that… so this is the place I need to fill in with more information.

Darwinian Agriculture: How understanding evolution can improve agriculture. My main takeaway from this book wasthat one set of genetics can not excel in both fertile and non fertile soil. If a plant is more productive in poor soil, it will be less productive in fertilie soil than a plant that has been bred to be very productive in fertile soil. I think this applies here we don’t want to dock certain populations for being low yielding in a fertile environment, when their genetic diversity/heterosis might only shine in a challanging conditions. But again, I think this might conflict with research papers, so I need to go back to both sides of the argument and dig in deeper.

Anyway, thanks Madison for bringing all this up! It’s really interesting to me. I want to make sure the language in the course (especially what’s written because I might have written that) is correct, so if you can point me to something specific in a lesson I will review and edit :slight_smile:

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