Minimum Breeding Pairs / Creating a Landrace

How many unique individuals would one need to start with to create a population with sufficient genetic diversity to avoid deleterious inbreeding?

One of my long term goals is to create a living seed bank, acclimated to the local conditions, which I and future generations could then harvest, or use as breeding stock in crosses. Basically, like how most long standing cannabis growing regions/cultures (India, Morocco, Jamaica, etc) do it.

BigNoise said:

How many unique individuals would one need to start with to create a population with sufficient genetic diversity to avoid deleterious inbreeding?

One of my long term goals is to create a living seed bank, acclimated to the local conditions, which I and future generations could then harvest, or use as breeding stock in crosses. Basically, like how most long standing cannabis growing regions/cultures (India, Morocco, Jamaica, etc) do it.

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Please elaborate?
Are you asking about unique individuals within a given line or are you talking about mixing/crossing several varieties together?

Either way...
I dont think there is a definitive answer.
The more the better...

Chimera would probably be the best person to answer this anyway.

for it to be heirloom/landrace i think you would want to open pollinate it with as many plants as possible, the idea is to keep as many genes as possible with selections you start narrowing down the genepool in the line

On one end of the spectrum, you would start with seeds from one plant. If you planted a few thousand seeds from that plant, and didn't allow any other plants to pollinate the population, eventually, you would start getting a lot of fucked up plants. Right?

The other end of the spectrum would be starting with some seeds from every source imaginable, basically a sampling of all the genetics on earth. This population wouldn't have any inbreeding problems.

Somewhere in between the two extremes, there is a minimum "chunk of the gene pool" that would allow a viable population to begin.

I am far from a botanist, but I know that when discussing fauna, "minimum breeding pairs" is a relatively common term. If this does not translate directly to plants, I would love for someone to educate me.

i don't think inbreeding depression is as bad as some people make it out to be.
its more about diversity, a landrace will have a majority of the same traits and should be identifiable as a whole, but you may still have say purple plants or short ones in the mix. If you used seed from those ones alone you may only get short or purple plants in the future. It may take years for it to be so inbred that its not worth growing but you may never see a green plant again.

I used to think a landrace would have inbreeding depression but it was explained to me that landraces are not homozygous they are heterozygous as such you dont see inbreeding depression.

I might have over simplified that answer but it seems to be what I recall being schooled on.

BigNoise said:

How many unique individuals would one need to start with to create a population with sufficient genetic diversity to avoid deleterious inbreeding?.

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Many would argue that all landraces are "polluted" from
introduced genetics.

Maybe.

If you had such "unique individuals", to prolong a cultivar
one would start with plants numbering in the thousands.

Many breeders convince themselves this is not the case,
so align yourself with the views that best support your
plot size and time allotted to your project.

Keep us posted, we're all counting on you.

Good thread!

First of all you are not going to create any landrace strains because you are not the almighty creator of life.

As for breeding with landrace genetics you will find that it is probably dependent on the strain you intend to breed with. Although a good selection of plants really would be necessary to complete the task correctly. Some might say 10 plants while the minority of true breeders here would definitely say a great deal more. Even with todays mess of supposedly inbreed lines, truly most are not really considered IBL just because they were mixed with the same strain.

You should imagine the past outdoor growers whom kept their genetics going for centuries. You really would want plant numbers in the 100's if not 1000's or 10's of 1000's to properly make seed with all the true aspects of a specific variety of plant.

It is not just a one and done mixing of females and males. That is just a beginning as future generations must also be bred out in order to really create a real stabilized creation.

LostTribe said:

First of all you are not going to create any landrace strains because you are not the almighty creator of life.

Click to expand...

Perhaps "create" is the wrong term. I guess it would be more "putting the pieces in place so a landrace can develop".

Landrace /= untouched by man, if that's what you're implying. How do you think Moroccan, Malawi, Mexican, Colombian, etc landraces came about? Any cannabis outside central/SE Asia was brought there by humans.

I mean, if for the rest of my life I sowed some surplus seed from my grows in the same area up in the hills, nobody else added any inputs, and nature took its course, at some point, those plants would become a landrace. Landrace implies a length of time where nature is the only selector.

I was just asking how big of a slice of the genetic pie one would need if they wanted to do a one-and-done planting to start a viable landrace.

I asked Chimera to stop in. Dont know if he will or not but I still stand on my first answer...

There is no definitive answer.

Are you going to include hemp?
There are literally thousands of varieties of drug types as well as fiber/seed types.

What really is your goal?
I believe an heirloom is something in the range of 20+ years of a particular variety being grown year to year from seed from the previous year.

Tossing a bunch of random genetics in a field to cross and collect and grow and cross and collect and grow and cross...
Does not a landrace make.

Why not select a landrace or few and see what, of them, can survive your particular area and maintain them?

BigNoise said:

Perhaps "create" is the wrong term. I guess it would be more "putting the pieces in place so a landrace can develop".

Landrace /= untouched by man, if that's what you're implying. How do you think Moroccan, Malawi, Mexican, Colombian, etc landraces came about? Any cannabis outside central/SE Asia was brought there by humans.

I mean, if for the rest of my life I sowed some surplus seed from my grows in the same area up in the hills, nobody else added any inputs, and nature took its course, at some point, those plants would become a landrace. Landrace implies a length of time where nature is the only selector.

I was just asking how big of a slice of the genetic pie one would need if they wanted to do a one-and-done planting to start a viable landrace.

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Hi bignoise.
the short answer is yes you can do it....
Unless you live in Antarctica.

when people talk about "landrace" strains they're talking about strains like India, morocco, Jamaica. etc.. but they are not true "landrace" strains. a true landrace strain is Asian hemp and or Indian hemp. no one really knows exactly where cannabis comes from? but I know what you mean by "landrace". the landraces we talk about were all "created" by man they are not wild strains. the local people have to collect seed at the end of each growing season. the seeds that get loose revert back to hemp in a dozen or so years. the locals call it "bushweed" because it sucks. no high.

so if you want to make a "landrace". you have to get plants that best suit your area. grow them out. select the best ones collect the seed year after year and kill all the ones that turn in to hemp aka bushweed.

and no you just can't throw seed down and come back in 10 years and have bomb weed. most cannabis seed will winter kill in most northern areas.


hope this helps.
good luck!

Landraces are usually not 100% fixed lines, but the genetic diversity within a landrace is almost always quite narrow.

Inbreeding is not necessarily deleterious. It is if it leads to inbreeding depression, but you'll have to present some evidence to even start to make the case that this is a significant issue in Cannabis.

If you want to genebank, then collect as far and as wide as you can and then fix your accessions. If you're preserving landraces, your accessions will be very very close but stable and not require more than a single individual to preserve. If you're preserving what passes for varieties these days, good luck but I wouldn't bother.

If you're trying to perform a low-pressure population development scheme to essentially generate your own landrace as a potential future donor of a package of locally-adapted alleles, then there is no minimum population size. Make cross(es) between things which you like but which you think might have large genetic distance, and then maintain as large a population size as possible until the generations stop varying. Bear in mind that even mild selection on your part will likely be much stronger than natural selection for the alleles which confer minor environment-specific benefits.

This whole landrace thing is interesting... seems like its similar to humans... take an asian guy and drop him in with the africans. His offspring will resemble him and his wife. As he is the only asian his offspring will marry an african and slowly the asian genetics diappear like they were never there.

Yes humans brought seeds with them as they migrated throughout time. People eventually settled in places and grew those seeds all over the world.

Every one of those Landrace strains you listed had not been hybridized at least not when they were first discovered by a bunch of stoner tourists....

MJ I am not the one selling seeds at a prime rate. I guess my dissatisfaction comes from the lines that I am sticking with. Some are cleaner versions of some favorites sure but only a select few have really been chosen over the years to work with. I only have a limited space to work with myself so the things I have done are even more aggressive than compared to what these guys with high plant counts are doing it seems at least.

Not everyone included its just you look at herbie's for instance and there are so many so called breeders on there its completely out of control and people are just buying into all these stupid names like the 839 different kinds of OG kush for instance. After a point who cares all they are doing at this point is screwing up the OG's traits. Just to be different and just to sell something they really can't stand by....sure they stand by it but its all hacked work from other people anyway so what matters I give up.

Back to the thread at hand sorry. I believe chimera would state that each variety would be different. How many traits are exhibited in the original stock? Which are classic traits? How many traits do you want to preserve?

The answer is as many as you can handle.

Thanks for the replies everyone.

IntelliGeneS said:

If you're trying to perform a low-pressure population development scheme to essentially generate your own landrace as a potential future donor of a package of locally-adapted alleles, then there is no minimum population size. Make cross(es) between things which you like but which you think might have large genetic distance, and then maintain as large a population size as possible until the generations stop varying. Bear in mind that even mild selection on your part will likely be much stronger than natural selection for the alleles which confer minor environment-specific benefits.

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That is a very good description of what I would like to do.

Basically, my dream would be to have semi-feral herb patches in various spots of my surrounding area (5 mile radius or so), which the local community could harvest freely, and which could be used as breeding stock for crossing with various "high grade" strains for backyard gardens. In short, I'm envious of the deep seated cannabis cultures in places like India, Morocco, Jamaica, etc., and would like to create such in my locale. Some communities gather acorns, some pick berries, some tap maples for syrup...some rub charras!

Well it really depends if you are looking to develop your own landraces or heirloom cultivars, as they are quite different besides the similarities. Basic difference between them is the genetic variability they offer and how much man selection has happened.

Landraces are basically made by the place where they grow. They are plant populations which are linked to a certain enviroment characteristics (ecotypes that have been semi-domesticated then). Basically they were wild plants that become highly adapted to a very specific enviroment (and its availability of nutrients, water, weather, soil, farming techniques...) with minimum selection by man. Thus they offer huge genetic variability which makes them very rustic, adaptable and sturdy overall. Yet they have enough common characteristics to be considered part of a certain recognisable plant population.

On the other hand, heirlooms are the result of man's work to preserve a traditional cultivar and they are fairly stable, homogeneus and always feature a handful of desirable characteristics, just like their ancestors. As opposed to landraces, they aren't defined by it's strict relation to a certain enviroment or ecosystem where they appeared. Besides what's commonly known, they aren't true open-pollinated plants because quite often only the seeds from best plants are kept. That's how the heirlooms reached their homogeneous and stable status with the years. They were also passed from one generation to another and preserved like that. Some people only consider pre-1945 seeds as heirlooms, the time when modern agriculture and hybrid crops become widespread in the market. Obviously Cannabis heirlooms are the oldschool, pre-80s and pre-skunk cultivars, or any cultivars predating the crazy hybridisation that happened since the introduction of Kush hashplants.

Developing your own landraces is easy, heirloom vegetable gardeners have been doing it for years. You just need to grow together in your local spot a similar number of seeds from a few dozens of different cultivars (heirlooms, open-pollinated or stable hibrids are preferred, the more different cultivars the best genetic diversity at the end) and let nature do her thing for a big period of time. The resulting seed crop of this big cross-pollination will be the begginning of a new possible landrace population that may keep evolving through the years with minimum farmer intervention and lots of survival-of-the-fittest selection. This promotes hybrid vigour and avoids inbreeding depression. This is basically how true landraces started everywhere.

In 10 years you may start finding intersting results and maybe in 25 years, you will have your very own local landrace, adapted to your own enviroment and still featuring a huge genetic potential against different growing conditions, pests, enviroments, diseases and cultural practices. Definitely much more adapted to your conditions than any hybrid you may grow. Maybe you can start with 50-100 seeds of 10-25 different strains. I know heirloom farmers who started growing up to 100 different cultivars together and ended with amazing results within 6-10 years.

Anyway keep in mind that this process would be a waste of time if your goals are related to mid-term breeding for "high grade" strains for backyard gardens. Because actually you will be reverting and discarding all the hard work done by men on drug strains: selecting and improving strains for their high, quality, resin yield, terpenes, potency, etc. You are letting them become semi-feral and loose all the drug traits they have been being bred for.

In this case, I'd rather try to preserve and keep a few heirloom populations going on as your breeding stock. But don't let them get crazy on their own but instead, keep improving and refining them as drug strains... just like what heirloom tomato or corn farmers do with their crops, saving seeds from the best plants until they end with a high-quality homogeneous population. Of course they will eventually become inbred on their own but then you can use this stable heirlooms for outcrosing to other heirlooms and breeding high grade hybrids as you said and the results will be much easier and will take much less time at the end. This what most plant breeders did after all.

Good luck with your project, sounds exciting to say the least.

Vibes.

Pretty cool objective.

I'm working toward a similar end.
Just getting started (4-5 yrs in) & expect a lifetime of fun & excitement.

Good luck with your project.

Mustafunk said:

Well it really depends if you are looking to develop your own landraces or heirloom cultivars, as they are quite different besides the similarities. Basic difference between them is the genetic variability they offer and how much man selection has happened.

Landraces are basically made by the place where they grow. They are plant populations which are linked to a certain enviroment characteristics (ecotypes then). Basically they were wild plants that become highly adapted to a very specific enviroment (and its availability of nutrients, water, weather, soil, farming techniques...) with minimum selection by man. Thus they offer huge genetic variability which makes them very rustic, adaptable and sturdy overall. Yet they have enough common characteristics to be considered part of a certain recognisable plant population.

On the other hand, heirlooms are the result of man's work to preserve a traditional cultivar and they are fairly stable, homogeneus and always feature a handful of desirable characteristics, just like their ancestors. As opposed to landraces, they aren't defined by it's strict relation to a certain enviroment or ecosystem where they appeared. Besides what's commonly known, they aren't true open-pollinated plants because once, only the seeds from best plants were kept. That's how the heirlooms reached their homogeneous and stable status with the years. They were also passed from one generation to another and preserved like that. Some people only consider pre-1945 seeds as heirlooms, the time when modern agriculture and hybrid crops become widespread in the market. Obviously Cannabis heirlooms are the oldschool, pre-80s and pre-skunk cultivars, prior to the crazy hybridisation that happened since then.

Developing your own landraces is easy, heirloom vegetable gardeners have been doing it for years. You just need to grow together in your local spot a similar number of seeds from a few dozens of different cultivars (heirlooms, open-pollinated or stable hibrids are preferred, the more different cultivars the best genetic diversity at the end) and let nature do her thing for a big period of time. The resulting seed crop of this big cross-pollination will be the begginning of a new possible landrace population that may keep evolving through the years with minimum farmer intervention and lots of survival-of-the-fittest selection. This promotes hybrid vigour and avoids inbreeding depression. This is basically how true landraces started everywhere.

In 10 years you may start finding intersting results and maybe in 25 years, you will have your very own local landrace, adapted to your own enviroment and still featuring a huge genetic potential against different growing conditions, pests, enviroments, diseases and cultural practices. Definitely much more adapted to your conditions than any hybrid you may grow. Maybe you can start with 50-100 seeds of 10-50 different strains. I know heirloom farmers who started growing up to 100 different cultivars together and ended with amazing results within 6-10 years.

Anyway keep in mind that this process would be a waste of time if your goals are related to mid-term breeding for "high grade" strains for backyard gardens. Because actually you will be reverting and discarding all the hard work done by men on drug strains: selecting and improving strains for their high, quality, resin yield, terpenes, potency, etc. You are letting them become semi-feral and loose all the drug traits they have been being bred for. In this case, I'd rather try to preserve and keep a few heirloom populations going on as your breeding stock. But don't let them go bananas on their own but instead keep improving and refining them as drug strains... just like what heirloom tomato or corn farmers do with their crops, saving seeds from the best plants until they end with a high-quality homogeneous population. Of course they will eventually become inbred on their own but then you can use this stable heirlooms for outcrosing to other heirlooms and breeding high grade hybrids as you said and the results will be much easier and will take much less time at the end. This what most plant breeders did after all.

Good luck with your project, sounds exciting to say the least.

Vibes.

Click to expand...

its all verry intresting read. but lets get to the facts here. its still just a new "cultivar/strain" you are creating.

landraces can not be created by the mand him self.
a landrace rly is what was there before. one HUGE gene pull of difrend phenos from that.

land races are our true gene pulls. with endless genns. you cant just make that from cross breeding some difrend cultivars over years. yes you can make a stable hybridized line this way. but its still just a cultivar/strain as all the other breeders products are out there.

sorry but i hate to see miss understandings about the difrence betwen landraces and cultivars. because its a verry big difrence right there. and ppl do read in thees subforums to learn stuff ya know

still a good read
rock on

I think what you're explaining is an IBL that is acclimated to your growing region, or climate.. ?